Form is the underlying structure of an icon, or how it is made. If you ignore the details of an icon and draw a line around the major shapes, do they form a square, a circle, a horizontal or vertical rectangle, a triangle or a more organic shape? The primary geometric shapes — circle, square and triangle — create a visually stable foundation for icon design. In our Corgi example by Kem Bardly, the dog’s head is made up of two triangles and two ellipses. Just as one would start a drawing by sketching the largest, simplest shapes and then refining towards greater and greater detail, one would start an icon from the simplest shapes and then add more detail.
Recognizability is a product of an icon’s essence or what makes an icon unique. Whether an icon works ultimately depends on how easily the viewer comprehends the object, idea or action it depicts. Recognizability includes showing the properties that the viewer commonly associates with that idea, but it can also include elements that are unique or unexpected, such as the heart for the Corgi’s nose. Remember that recognizability refers not only to comprehension of the object, idea or action being depicted, but also to recognition of your unique icon set. In this respect, aesthetic unity and recognition can, and often do, overlap.
The elements that are shared within a single icon and across an icon set are what we call the aesthetic unity. These elements are things like rounded or square corners, the specific size of corners (2 pixels, 4 pixels, etc.), limited and consistent line weights (2 pixels, 4 pixels, etc.), the style (flat, line, filled line or glyph), the color palette and more. The aesthetic unity of a set is the collection of design elements and/or choices you repeat throughout the set to visually tie it together as a cohesive whole.
