The Fifteen Properties and Furniture Design

Alexander’s Fifteen Properties are described in detail below.  Because the properties are highly interdependent and mutually supporting, I’ve emphasized this important feature by highlighting in red the other properties that make the most significant contribution to the property under consideration.  For anyone new to Alexander’s Fifteen Properties, I recommend that you read through them quickly to get a sense of their scope and then return to focus on them individually.

The Fifteen Properties are best understood in the context of actual examples of which there are many in both good traditional and contemporary work.  Unless otherwise noted, the examples are from my own (mostly) Shaker-inspired work. The two exceptions are the Shaker sewing desk which is somewhat “generic” and for which I have no reference on the source of the photo, and the photo of the sideboard by Garrett Hack, for which permission was granted. While good Shaker-style pieces exhibit the Fifteen Properties, they are usually understated and therefore less useful as initial examples.  Other examples are supplied by links to other sites since in many cases it is not clear who may hold copyrights, if any.



All centers are made up of smaller centers, and all of the centers must be strong.   Strong centers should occur at all Levels of Scale. Typically they should exhibit Good Shape, create Positive Space, and have Local Symmetries.  Strong centers will also be characterized by good Boundaries  and Contrast (color or texture).  They may also Echos  of other centers, and centers may exhibit Alternating Repetition.  Strong Centers are often formed by nesting them.  Strong Centers are created by other strong centers within them or outside them.

Good pieces of furniture always have strong and beautiful centers at all levels of scale.  All of the centers will be mutually supporting in such a way as to make the piece whole and at unity with itself. The larger centers (in outline form) will almost always be very simple in shape, often being made up of only squares, rectangles and triangles (some of which may contain curved shapes.)

Shaker-style Writing Desk

The Shaker-style writing desk drawers form centers, but these centers are relatively weak because they do not have much support from the other properties.

The Shaker-style bookcase below has similar drawers, but the centers that they form are somewhat more intense because they have the support of boundaries (in the form of edge bands and the bead).

Shaker-style Bookcase

The closeup of one drawer shows the greater intensity of the centers as compared to a plain flat-faced drawer.

The intensity of these drawers could have been significantly increased by the use of contrasting wood or highly figured wood, but that was not the intent for this piece.  The lack of intensity is not unusual in Shaker-style works, and actually contributes to its particular character (see Simplicity and Inner Calm and a Shaker-inspired example by Garrett Hack below.)

Bookcase Drawer Detail

The Asian-inspired credenza by Hikmet Sackman has many  very strong centers formed by the highly figured panels (both large and small) which contrast with the color and grain orientation of not only their frames, but also the surrounding case.  Even the curves at the top and bottom intensify the smaller centers.

A 17th Century inspired wedding chest by John P. McCormack  has beautifully intense centers formed by the colored panels and their borders.

Interestingly, strong centers can also be formed by restraining detail. The Shaker style sideboard by Garrett Hack (like many Shaker pieces) has strong visual centers that arise out of simplicity rather than complexity.  The simple turned legs, the highly figured top, and the contrasting and carefully arranged drawer fronts with dark knobs work together in a remarkable way to create strong centers. Further addition (or removal) of ornament would diminish the honest and direct appeal of this piece. Good contemporary furniture, like this piece, often uses restraint to create strong visual centers. Strong centers are fundamental to good design, and a truly good piece of furniture will always have multiple strong centers because it is these centers that give the piece visual coherence and interest.



Create a range of sizes of Strong Centers – big, medium, small, and very small, and link them together by small whole number ratios (1:2, 2:3, 3:4, 3:5 and 4:5 are typical) so that they have good proportions relative to each other and to the whole. The centers of each scale must actually support the centers in each other scale, otherwise there will be only the appearance of having levels of scale. The best examples of levels of scale are found in nature: For example, a tree where the large trunk supports the large limbs which branch off into smaller limbs, then twigs, then leaves (which also have a full range of scale from leaf to vein, and even to the cells themselves.) To skip any level of scale in the tree would do damage to the whole. Levels of Scale must also be “human” in size, often relating to parts of the human body in scale. (See Jim Tolpins article “Designing by Foot, Hand, & Eye”, Popular Woodworking, August 1020 for a very thoughtful approach to “human” design.)  Through multiple Levels of Scale a large center is made stronger by smaller centers within it and still larger ones outside it.

The traditional Classical Orders embody a wealth of accumulated information related to Levels of Scale and can often be used to set all the major levels of scale in a traditional piece of furniture.  (See George Walker’s post related to the classical orders and human size.)

As in the tree, levels of scale from large to small must be present if the piece is to be perceived as a whole.  Levels of Scale in furniture often result naturally from sub-dividing the larger centers.  A single piece of trim can exhibit multiple levels of scale, for example a piece of cornice molding may have several visual bands each of which is in a small whole number ratios to the others (perhaps in depth as well as width.)  Levels of Scale exist in three dimensions as well as two – always think in terms of “sculpting” 3D space as a design unfolds.

The hall table shown below demonstrates good levels of scale in that the height of the apron is about 3x the maximum diameter of the legs; the thickness of the top is about 1/2x the maximum diameter of the leg; the dark bases of the legs are approximately 1x the size of the turned transitions near the top of the legs; the overhang (on the ends) is about 1/2x the height of the apron, etc.  If the apron were twice the height as shown, the table would appear awkward.  Note also that the overall shape is approximately a 2:1 rectangle.

Hall Table

In the turned lidded rice bowl by Butch Smuts the maximum diameter is about 3-4 times the diameter of the base (as well as the dark center at the top.)  The height of the bowl cover is about 3 times the height of the lighter bowl portion. The various components of the top (triangles, openings, etc.) relate to each other in relatively small whole number proportions.



Boundaries almost always help form and strengthen centers.  Boundaries give a center focus and intensity, and connect the center to surrounding centers.  A good boundary both separates and unites.  Good boundaries are of the same order of magnitude (area) as the center which it bounds.  The actual boundary must be thought of as large (though the boundary, itself, may be created from other smaller boundaries.) Boundaries can function in all three dimensions by creating shadow lines or standing out from the surface (e.g. trim pieces, cornice moldings, etc.) Boundaries themselves are Strong Centers, are made up of other Boundaries, exhibit Positive Space and Good Shape Contrasting color or texture can help form a boundary. Boundaries may exhibit Alternating Repetition, Local Symmetries, Echoes, Gradients, Deep Interlock and Ambiguity, and Levels of Scale.  Boundaries are responsible for nearly all the differentiation between the various centers and, as such, must be given much attention. Boundaries strengthen centers and unite them with other centers.

Boundaries in furniture can be formed by rails, stiles, reveals, step-backs, pieces of trim (which often consist of several boundaries), string or other inlay, cock beading and other small bands of trim.  Boundaries can also be formed by a change in wood species (either through color or texture, or they way each reflects light.) Complex figure in wood (like a crotch veneer) can also be used to establish a boundary.

This chessboard has boundaries which are formed by the inlay and intensified by the change in wood species from the playing field to the border.




Repetition intensifies centers, but simple repetition is not enough.  The repetition must result from the repetition of primary and secondary centers that interlock.  The spaces between the repeating centers are as important as the centers themselves.  Alternating Repetition is more like an oscillation or “wave effect” that radiates throughout the whole.  The elements or centers responsible for the Alternating Repetition must themselves be beautifully proportioned and differentiated.  The centers used for Alternating Repetition must have all of the characteristics of strong centers themselves such as Levels of Scale, Boundaries, etc. Insertion of repeating centers between other centers strengthens all of the centers.

Alternating repetition is best demonstrated by example. Assume for a moment that the characters “x”, “<” and “>” represent three strong centers. Simple simple repetition of a single center like “xxxx” (think dentil molding) creates some interest, but not much.  Simple repetition using two centers “x>x>x>x” (think egg and dart) may be somewhat better, but alternating repetition ”    ” has the potential to create much more significant interest (even with these simple characters.)  Evenly spaced finger joints or evenly spaced pins and tails along a dovetailed  edge “x x x x x” may be structurally sound, but it is the repetition of small pins and wider tails “x    x    x    x    x” that begins to bring life to the sequence. The small components in good furniture often come to life when they are arranged to create alternating repetition.

Table Drawer

Some of the beauty of well executed dovetails lies in making sure that the pins are much smaller than the tails. The small pin/large tail combination creates an alternating repetition along the edge of a cabinet that strengthens existing centers and creates a visually interesting border.  These centers could be further strengthened by using highly contrasting woods. Curves and carved spaces can also exhibit Alternating Repetition.



Positive Spaces are spaces that are substantial in and of themselves.  They often swell outward (convex), but rarely inward (concave).  Spaces cannot be just leftovers formed by the adjacent spaces.  Always create spaces that are not only positive themselves, but that create adjacent spaces that are also positive.  All of the spaces must fit together in such a way that there are no “leftover” spaces.  Often, the outline of one space will automatically create an adjacent space that is also positive. Positive Space causes a center to draw strength from immediately adjacent centers.

The raised portion of a panel automatically creates an equally positive space around it (the reveal, or sloping portion of the panel), which in turn creates a positive space for the frame of the raised panel door, and so on. Positive space must be maintained at all levels throughout a piece of furniture.

Positive Space exists in three dimensions as well as two.  For example the open space under a table or night stand is just as important as the space occupied by the top, aprons and legs. The spaces between the rungs or spindles in a chair are just as important, if not more so, than the rungs and spindles themselves. The dark green of traditional Windsor chairs is important because it reinforces the positive spaces formed by all the members. In this case, the dark color creates contrast which helps define the open spaces. Only when every space in a piece of furniture is made positive will the whole come to life.



Centers always contain hard to quantify but beautiful, gorgeous, powerful shapes, often subtile and complex.  Good shape always has multiple centers which are themselves have good shape.  Good shape has a high degree of internal symmetry which is almost always bilateral. Good Shape usually has well-marked centers (but not always the geometric center), and adjacent spaces that exhibit Positive Space. Good shape is highly differentiated from the surrounding parts (often by Boundaries or Contrast) , and is relatively compact fitting in spaces with very small whole number ratios (1:1, 1:2 but rarely 1:4 or higher). Good Shape also creates a sense of closure or completeness. Good shape always strengthens a Center.

Good shape is almost always composed of squares, line segments, arrowheads, hooks, triangles, rows of dots, circles, rosettes, diamonds, S-shapes, half circles, stars, steps, crosses, waves, spirals, trees and octagons.  Circles are less common because it is hard to create positive space around them.

Almost all natural systems form closed, beautifully shapes spaces. Trees almost always have beautiful shapes, as do their leaves. A Good Shape has a geometry that reinforces or helps form a Strong Center.

Good furniture must have the quality of Good Shape and proportions that are appropriate to the piece and that relate well to the surrounding room.  Once the overall shape is determined, the concept of good shape must be extended down to the each and every detail. Are the rails and stiles in a door the right shape (length and width)? Do the end panels have a good shape? Do the legs have the right taper or turned shape? Is the knob the right length and width, and is it placed in the best possible location? Is the reveal around the drawer a good shape? Does the profile on the trim have the right shape? Color can help create good shape. A good example of this is found in the old

Shaker Boxes

Shaker oval boxes painted with beautiful, pure, and sometimes very intense colors. The colors reinforce the good shape – take away the color, and these boxes become much more commonplace (which is one reason that shellac, oil, and varnish finishes on these boxes usually diminish rather than enhance them.)



Local symmetries are all pervasive in the world around us. Overall  symmetry rarely points to life, but Local Symmetries do.  Asymmetry is usually found only at larger scales. And the larger asymmetries are meaningful only when they are supported by many, many smaller sub-symmetries. The Local Symmetries become woven together to make a whole that is rarely symmetrical, or only roughly so. Local Symmetries always strengthen the larger center of which they are a part.

Quite often, larger built-ins and pieces of furniture benefit from an overall asymmetry, provided that there is strong symmetry in the next smaller scale. Large symmetries in built-ins are ‘safe’, but more often than not, boring. Asymmetry helps creates a certain movement along a piece or wall, and must be utilized whenever appropriate.  Often this movement should be upward in a tall piece, and horizontal in a lower piece, although not always.  When in doubt about how to form a Strong Center, include some Local Symmetries as part of that center, or between two centers.

Shaker Sewing Desk

The often reproduced classic Shaker sewing desk is, like many Shaker pieces, strongly asymmetrical as a whole. Some of the drawers are even placed on the side rather than on the front bringing a very strong sense of asymmetry! But the larger asymmetry is supported by many strong local symmetries in the front panels and the drawers (which interestingly, for a Shaker piece, are not graduated, so strong is the need for the local symmetry.)  I cannot credit this photo to a specific craftsman since it is like one of many that I have seen or photographed.

Most other pieces shown in this article have strong symmetries along a central vertical axis, but often exhibit asymmetry on the horizontal axis. It is the interplay between the larger asymmetries (along either axis) and the local symmetries they contain that creates and sustains lasting interest in a piece of furniture.



There must be a deep underlying similarity among the various elements, almost like a family resemblance.  Like family resemblances, Echoes are deeper than superficial similarities between parts or symmetries.  Echoes often depend the angles or families of angles formed by the various parts. In most natural systems various parts are echoed by other parts of the system. The echoes are not precise mirror images, but rather share like features. To bring echoes to life, focus mostly on the geometric angles, lines, and shapes and use the recursively.

Demilune Table

In good furniture various lines, angles, and shapes, to name a few, must have echoes in other locations. The echoes help give the piece its overall wholeness. Without them, the piece will seem as if it is headed in several directions, none of which is related to the others and it will lack unity.  Regulating lines can be indicative of Echoes that are often subtile but significant.

The demilune table contains echoes in the shapes of the inlay, echoes between the leg bottoms and the dark inserts and others.  There is a “family resemblance” in the various parts that give the piece a sense of unity.



Gradients are formed whenever some property of a system varies systematically – a slow change across space in response to changing conditions. Gradients can result from changes in size, spacing, intensity, color, and character.  Gradients are formed by centers and also form centers.  Gradients (even subtile ones) are often very significant in furniture. They are closely related to levels of scale, and often help reinforce the levels of scale.

Chest of Drawers

A chest of drawers with each drawer precisely the same size may be easier to construct, but make the bottom drawer larger and gradually decrease the size of each subsequent drawer even slightly while moving up the case and the piece will come alive.  The drawers in the chest to the right are graduated in pairs rather than individually. The top and bottom rails of a door should only rarely be identical in height; if the bottom rail is slightly larger than the upper, a sense of movement (however subtile) is created upward along the door.  A Windsor chair back is visually interesting and alive because the spindles are graduated both along their length and in length from the longest center spindle to the shortest outer spindles. They are also symmetrical, each spindle echoed by another along a vertical axis.



Interlock sometimes results from centers being hooked together, and sometimes through spacial ambiguity where something belongs both to a center and also to its surroundings.  In all cases, the interlock ties things together very strongly.  Deep interlock and ambiguity develop when the various parts of a piece are arranged in such a way that it becomes very hard to have one part without the support of another. It becomes very ambiguous as to exactly where one part ends and another starts. When deep interlock and ambiguity are present, the entire piece will be perceived as a ‘whole’ because it is difficult to separate it into parts.  With Deep Interlock and Ambiguity two centers become strongly attached and held together by a third set of centers that somehow belongs to both other centers.

Deeply Interlocked Pattern

In furniture, dovetails exhibit interlock (with varying degrees of deepness depending on the sizing and spacing of the pins.)  Sometimes fine inlay detailing can help create this kind of interlock. Sometimes the shapes of larger parts can be arranged to provide the same kind of interlock.

Although not incorporated into a piece of furniture, the sketch to the left exhibits both deep interlock (which part locks to which, or do they all lock together?), and ambiguity (can you tell which part belongs to which?) Can you find the slightly stylized letter “A”? (I count at least 7 of them imbedded in the pattern.) The pattern also has strong alternating repetition, echoes, positive space (is there any part that is “left over”?) and strong local symmetries.  Variations on this pattern are often found in antique oriental rugs.  I have yet to figure out how to create this pattern in a piece of furniture!  Perhaps by using inlay?



Intense contrast, usually more intense than one might think necessary, increases the life of a center. The contrast often creates a unity that comes from distinctiveness and differentiation.  Contrast should create deeper feeling and if it does not, it is not good contrast. Contrast can be in color, value, texture, shape, size, angle, reflection of light, etc. – almost anything that creates a distinction. Each center in a strong contrast is always set off and strengthened by the other.

Furniture without good contrast is likely to be perceived as simply boring. Sometimes good figure in wood can help create contrast and interest. Sometimes the size of various parts themselves help create contrast. In some pieces the use of several contrasting species of wood is effective. The shadow lines of good trim can create effective and intense contrast sometimes exceeding that of other elements.

The chessboard shown above gets some of its life from the contrast between the squares in the playing field.  If the large border (outside the small strip of inlay) were darker, the board might gain additional life.



Roughness does not imply imperfection, rather it is a result of elements that of necessity have to adjust to their surroundings.  Roughness results from a precision that is much deeper than pure mechanical “grid-like” precision.   Roughness cannot be deliberately or consciously created, rather it arises out of what is required.  Roughness allows the overall design to relax and be itself. With roughness, a center is strengthened by irregularities in sizes, shapes, and the arrangements of other nearby centers.  The fireside bench shown below exhibits at least some roughness in that the live edges were maintained even though they given a more refined edge. The top is completely irregular although the photograph does not emphasize this very well.

Fireside Bench I

Note that Roughness does not mean rough in the sense of poor quality workmanship. Rather, it describes a quality that is present in all of nature, and must also be expressed in fine furniture.  A piece of precisely dead-flat steel may have its uses, but aesthetically it has little to offer. Similarly, a dead-flat table top, perhaps finished with a high-gloss mirror-like finish, may be technically perfect, but it has far less to offer aesthetically than we have come to believe.

Trestle Table with Hand-planed Top

A nicely hand-planed table top with its subtile undulations that reflect light in subtile, but noticeable patterns, creates visual interest and invites touch. It is in this sense “rough”, but almost certainly more satisfying then the ‘perfect’ top. For similar reasons, fine wood furniture is often best displayed against the ‘roughness’ of plaster walls and painted trim, or even against the substantial roughness of an antique floor.



The most profound centers have at their heart a void of infinite depth at the center that contrasts deeply with the surrounding centers. This Void creates silence.  The fine detail of complex systems in our world often occur around a larger less ‘busy’ center. This center forms a void in the system that is a necessary feature. In nature, ponds and fields can form such centers.  Center aisles in barns or churches function similarly.  The Void is not necessarily totally empty space – it can be made up of smaller repeating centers that simply contrast with other larger centers.

As ornament and detail are added to a piece of furniture, it is important that they be added near, and function in support of less ‘busy’ areas — areas that are void of great detail, or whose detail is much finer in nature. By adding ornament and detail in this manner (rather than everywhere), not only is the ornament and detail highlighted by the void, but the void itself becomes a stronger center bringing life to the piece.



Wholeness usually expresses itself in geometric simplicity and purity. There is a slowness, majesty, and inner calm where everything unnecessary has been removed. This property is related to the concept of a void, but its purpose is different. The void helps ‘organize’ the details; but, simplicity and inner calm result when every detail that does not fully support the whole is removed.

Garrett Hack Table

It is possible to add too much detail and ornament to a piece of furniture. When this happens the whole is diminished rather than improved. Too much of a good thing becomes ‘not-a-good-thing.’ The best classic examples of simplicity and inner calm are found in good Shaker items. The Shakers understood, perhaps better than others, how to create items full of beauty and depth using simple shapes (overall and in the parts as well), remarkably little ornament or detail, colors worked into the wood, and even unusual arrangements (usually arising from the intended function.)

The Shaker style sideboard by Garrett Hack (like many Shaker pieces) has strong visual centers that arise out of simplicity rather than complexity.  The simple turned legs, the highly figured top, and the contrasting and carefully arranged drawer fronts with dark knobs work together in a remarkable way to create strong centers. Further addition (or removal) of ornament would diminish the honest and direct appeal of this piece.



Deep Interconnectedness (my term) or Not Separateness (Alexander’s term) arises when something is truly at one with the world around it.  The Not-Separate item retains its character but is yet indistinguishable from its surroundings.  It exists in harmony with and by blending with its surroundings. Not separateness or Deep Interconnectedness refers to the observable fact that no system exists in isolation from other systems. Not-Separateness arises almost unconsciously when the border of a center is fragmented rather than a continuous line, especially if it has some gradient with decreasing scale that helps it “melt” into the surrounding area (while still being distinct.)

In furniture, not-separateness occurs when each and every part exists in the context of all the other parts. When a piece of furniture is at unity with itself, ‘not separateness’ will be evident at all levels of scale. In addition, furniture and built-ins must also be ‘Not-Separate’ from the rooms they were designed for and in which they are placed and used. Experienced furniture builders will always keep the whole in mind as the design unfolds.



The Fifteen Properties or qualities of good design noted above are significant in good furniture design and must be given careful attention. They form the very core of a good piece of furniture, especially when they are present and deeply imbedded such that each one supports and reinforces the others.  Most of these properties can be expressed in bold or subtile ways, but it is these properties or qualities that allow endless variations in designs all of which have great wholeness, depth,  and lasting interest. Furniture that lacks these qualities rarely survives the test of time.

Remember, these properties are not “parts” that one adds to an object.  They must arise in the process of “unfolding” the object if they are to be real and substantial.  For this reason, developing these qualities in a real life application very is challenging, particularly because they are so strongly interrelated and highly dependent on each other. But a working knowledge of these qualities should provide significant guidance in the process of designing and creating good furniture.  I strongly encourage you to read Alexanders work for a more in-depth understanding of these properties and how they emerge.  Just getting this summary in writing has challenged my ability to understand and express these properties.

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