There are many kinds of shape and form, and as many words to describe them. Hard materials can be described as round, square, diamond-shaped, oblong, and rectangular. Plants can be described as pyramidal, pillar, column, fastigiate, flat, prostrate, drooping, weeping, and trailing.
Although the three basic dimensions of size, length, width and height, give an indication of the shape of an object, its characteristic outline or form is much more complex. More than anything else, we recognize an object by its outline; shape first, then color and texture. A black and white photograph has no color but is still instantly recognizable. Even a silhouette is enough.
Subconsciously, our eyes and brain constantly analyze the shapes that surround us. An interesting garden should be a combination of interesting shapes – a richness to delight the eye.