Design Patterns: Elements of Reusable Object-Oriented Design

Erhard Gammer, Reinhold Helm, Rolf Johansson, Jan Vlissopoulos

Excerpts from the catalogue, first published by Addison-Wesley, 1994

Reviewed in The Journal of the Textile Society of America, Vol. 7, No. 2, Spring 1995

Preface

This catalogue documents twenty-three recurring motifs in the decorative arts — patterns that appear, with local variation, across centuries and cultures, and that solve recurring problems in the organisation of visual space. We call them design patterns: reusable solutions to common problems in object-oriented design, by which we mean design oriented around a central object or motif.

The catalogue has attracted criticism, some of it justified. We are told that we have encouraged a generation of young designers to reach for a pattern when they should be reaching for an original idea — that the availability of a ready-made Singleton or Adapter has made it too easy to avoid the difficult work of invention. We do not deny this. A pattern book is a tool, and like all tools it can substitute for thought. Owen Jones, in The Grammar of Ornament (1856), issued the same warning about his own plates: “The student who merely copies these illustrations has learnt nothing.” We echo his admonition and share his expectation that it will be ignored.

A note on authorship. This catalogue is a collaboration between four designers trained in different traditions — Swiss (Gammer), Australian (Helm), American (Johnson), and Greek-American (Vlissopoulos) — and our disagreements have been frequent and occasionally heated. Where we could not agree, we have said so in the text. The reader may draw her own conclusions.

Singleton

Intent. To organise the visual field around a single, unrepeated central medallion, ensuring that the eye has exactly one focal point.

Context. The Singleton is appropriate when a surface must communicate hierarchy — when one element must dominate and all others must defer. It appears in Persian carpet design (the central toranj medallion), in Rose Window compositions, and in the heraldic tradition, where the coat of arms occupies the centre and the supporters and mantling exist only to frame it.

Structure. A single motif, typically circular or polygonal, occupies the geometric centre of the field. Surrounding elements are subordinated through scale, colour saturation, or density of detail. The ground — the negative space around the central object — is as important as the object itself; a Singleton on a cluttered ground is not a Singleton but a motif that has failed to achieve dominance.

Known Uses. The toranj in Safavid carpets; the rose windows of Notre-Dame and Chartres; the central roundel in Byzantine floor mosaics; the presidential seal. Also, regrettably, the feature wall in contemporary interior design, where a single oversized clock or mirror is placed on an otherwise empty surface, producing a Singleton of no particular merit.

Related Patterns. Facade (when the Singleton conceals underlying complexity), Observer (when the central element appears to watch the viewer).

[Editorial note: Gammer wishes to record that the Singleton is the most abused pattern in the catalogue. “Every student who cannot think of a composition puts a circle in the middle and calls it a Singleton. This is not design. This is geometry.” Johnson disagrees: “The Singleton is democratic. It asks nothing of the viewer except that they look at the centre. What’s wrong with that?” The disagreement is unresolved.]

Observer

Intent. A repeating motif of eyes, faces, or watchful figures arranged so that the surface appears to regard the viewer from multiple points simultaneously.

Context. The Observer pattern exploits the human neurological sensitivity to being watched. It is among the oldest patterns in the decorative arts — the oculus motifs on Neolithic pottery may be Observers — and it appears wherever a surface is intended to be apotropaic, that is, to ward off evil by returning the gaze.

Structure. The fundamental unit is an eye or eye-like form, repeated at regular intervals across the field. The intervals matter. Too close, and the effect is oppressive; too far apart, and the individual eyes lose their collective power. The optimal density — empirically determined by Ottoman tileworkers over centuries of practice — is approximately one eye per twelve to fifteen square centimetres on a wall tile, adjusted for viewing distance. The eyes need not be identical; slight variations in pupil direction create the unsettling impression that the surface is tracking movement.

Known Uses. The nazar (evil eye) motif in Turkish and Greek decorative arts; the peacock-feather pattern in Art Nouveau textiles (the “eye” of the feather functioning as an Observer); the thousand-eyed ceiling of the Doge’s Palace in Venice; the recurring eye motifs in Coptic textiles of the fourth and fifth centuries.

[Vlissopoulos writes: “I grew up in a house where every doorway had a glass eye hung above it. My grandmother replaced them when they cracked, which she said meant they had absorbed a curse. The Observer is not a decorative choice. It is a theological commitment. Designers who use it for ‘visual interest’ without understanding its protective function are, in my view, committing a minor blasphemy. Helm says I am being dramatic. Helm did not grow up in my grandmother’s house.”]

Related Patterns. Singleton (when a single Observer dominates), Facade (when the eyes conceal rather than reveal).

Factory

Intent. The reproduction of a handcraft motif by mechanical means — specifically, the industrial loom — such that the pattern retains the appearance of handwork while being produced at scale.

Context. The Factory pattern emerged in the early nineteenth century with the Jacquard loom, which allowed complex figured fabrics previously requiring weeks of hand-weaving to be produced in hours. The pattern is identical in form to its handmade antecedent. The difference is in provenance, not appearance — and this difference is the source of the pattern’s central controversy.

Structure. A Factory pattern is defined not by its visual properties but by its mode of production. Any motif — floral, geometric, figurative — can be rendered as a Factory pattern. The identifying characteristic is mechanical regularity: the repeat is exact, the tension is uniform, the selvedge is clean. In a handwoven textile, these properties are aspirational. In a Factory textile, they are inevitable, and this inevitability is what troubles the connoisseur.

Known Uses. Jacquard-woven silk brocades imitating Lyon hand-weaving; block-printed cottons imitating Indian chintz; machine-tufted carpets imitating Persian knot-work; William Morris’s deliberate rejection of the Factory in favour of hand-printing at Kelmscott, which was itself a kind of anti-Factory Factory, producing handmade textiles at prices only the wealthy could afford.

[Johnson: “The Factory democratised beauty. Before the Jacquard loom, a figured silk was a luxury. After it, a shopkeeper’s wife could hang damask curtains. I consider this an unambiguous good.” Gammer: “The shopkeeper’s wife could hang damask curtains that were not damask. She could own a pattern that was no longer a pattern but a photocopy of a pattern. The Factory does not democratise beauty. It democratises the appearance of beauty, which is not the same thing.” This argument recurs at every editorial meeting and is not expected to resolve.]

Related Patterns. Adapter (when a handcraft motif must be modified to accommodate mechanical reproduction), Facade (when the Factory conceals its own mechanical origin).

Adapter

Intent. A border or transitional motif that reconciles two incompatible central patterns, allowing them to coexist on the same surface.

Context. The Adapter is a problem-solving pattern. It arises whenever a designer must combine motifs from different traditions — Islamic geometric interlace alongside European floral naturalism, for instance, or Chinese cloud-scroll borders framing an Indian paisley field. The motifs were not designed to be neighbours. The Adapter makes them neighbours.

Structure. The Adapter occupies the boundary zone between two pattern regions. It must share visual properties with both — picking up the colour palette of one and the geometric logic of the other, or modulating scale gradually so that the transition is felt as a gradient rather than a seam. The most elegant Adapters are invisible: the viewer perceives a unified surface without noticing the mediation. The clumsy Adapter calls attention to the boundary, which defeats its purpose.

Known Uses. The transitional borders in Mughal carpets combining Persian floral motifs with Hindu geometric grounds; the rope and bead mouldings in Neoclassical interiors that adapt between Greek key friezes and Roman acanthus panels; the Art Deco borders that reconcile Egyptian geometric forms with Modernist abstraction. The entire history of colonial decorative arts is, in a sense, a history of Adapters.

Related Patterns. Decorator (which adds richness without reconciling incompatibles), Strategy (which varies technique while preserving motif).

Decorator

Intent. An ornamental frame, border, or overlay that enriches an existing pattern without altering the underlying design.

Context. The Decorator is applied after the primary composition is established. It adds complexity, depth, or visual texture to a surface that is already complete in itself. The key property is that the Decorator can be removed — or replaced with a different Decorator — without disturbing the pattern beneath. This distinguishes it from the Adapter, which is structural, and from the Facade, which is concealing.

Structure. The Decorator wraps the primary motif. Common forms include gilded borders around painted panels, embroidered edges on woven textiles, and the elaborate strapwork frames that surround Elizabethan portrait miniatures. Multiple Decorators can be layered: a painted panel may have a gilded inner border, a carved outer frame, and an architectural surround, each a Decorator upon a Decorator.

Known Uses. The successive frames around Byzantine icons (the painted border, the metal riza, the jewelled oklad); the layered borders in Mamluk carpets; the gilded frames around Renaissance altarpieces, which are often more expensive than the paintings they contain — a Decorator that has exceeded its source.

Related Patterns. Facade (conceals rather than enriches), Adapter (reconciles rather than ornaments), Singleton (a Decorator applied to a Singleton creates the Medallion-and-Frame composition that dominates classical carpet design).

Facade

Intent. A simplified exterior motif that conceals complex, irregular, or unsightly structural patterning beneath the visible surface.

Context. The Facade is the public face of a pattern. It is common in architectural tilework, where the visible ceramic surface must present a serene geometric order while concealing the rough masonry, uneven mortar joints, and ad hoc structural repairs underneath. The Facade does not merely simplify; it actively misrepresents. The viewer is meant to believe that the entire structure is as orderly as the visible surface.

Structure. A regular, repeating motif — typically geometric, because geometry implies precision — applied to the outermost layer. The Facade must be self-sufficient: it should not require the viewer to understand what lies beneath. Indeed, the success of the Facade is measured by the degree to which the viewer never considers the question.

Known Uses. The tilework facades of Timurid mosques, where stunningly precise geometric patterns cover walls of unremarkable mud brick; the stucco facades of Georgian townhouses, where a smooth white face conceals rubble-filled walls; the plaster ceiling roses of Victorian houses, which simulate carved stone over lath and horsehair. The Potemkin village is a Facade without a building, which is either the purest expression of the pattern or its reductio ad absurdum.

Related Patterns. Decorator (enriches rather than conceals), Factory (which conceals its mode of production specifically).

Strategy

Intent. A composition in which the central motif remains constant across instances while the technique of execution varies according to the medium.

Context. The same floral motif — say, a Tudor rose — might be rendered in cross-stitch on linen, in crewelwork on wool, in silk satin stitch on velvet, or in carved relief on oak. The motif is invariant. The strategy of execution changes to suit the material. The pattern is defined at a level of abstraction above any particular medium, and each medium provides its own interpretation.

Structure. A canonical motif (the “intent”) is documented in a medium-independent form — typically a paper cartoon or, in Islamic practice, a pounce pattern of pricked holes through which charcoal dust is blown onto the target surface. The artisan then executes the motif using whichever technique is appropriate: knotting for carpet, glazing for tile, stitching for textile, carving for wood. The motif is recognisably the same across all media, but each medium contributes properties — the sheen of silk, the depth of carved oak, the luminosity of glazed ceramic — that the paper cartoon cannot anticipate.

Known Uses. The arabesque, which appears in virtually every Islamic medium from plaster to metal to textile; the acanthus scroll, which migrates from Greek stone carving to Roman mosaic to Renaissance painting to Victorian wallpaper with the motif intact and the technique transformed at each step.

Related Patterns. Factory (the industrial negation of Strategy, in which a single technique is used for all media), Adapter (which mediates between incompatible strategies).

Afterword

Twenty-three patterns do not exhaust the decorative arts, any more than an alphabet exhausts a language. They are elements — starting points — and the designer who uses them well will combine, subvert, and eventually transcend them. The designer who merely applies them will produce competent work that is never surprising, which is to say: work that fulfils the letter of design while missing its spirit. We have written this catalogue in the hope of the former outcome and the expectation of the latter.

— E.G., R.H., R.J., J.V. Zurich, Sydney, Urbana, and Chappaqua, 1994