Fig. 2:  Dynamic simplicity (the figure on the right is more dynamic than that on the left)

Diagonality, rotation, non-horizontality and non-verticality all have, as we've just seen, a strong motion implication (Fig. 3). Physical world around us offers plenty of examples showing that any non-architectonic object is either falling, or jumping, or simply unstable - in a word, dynamic.

Fig. 3:  Dynamic rotation

Slant, or skew, is a special case of rotation with some parts of the objects's outline still horizontal or vertical, and others, rotated at some angle (Fig. 4). Here, the architectonic parts of the contour define the direction of the motion, while the slanted parts add force to it and make it more expressive. Physical analogs for this feature would include deformations in moving objects caused by inertia or aerodynamic drag. It is this effect that makes sans-serif italic typefaces so expressively dynamic - especially when compared to serif italic which are not slanted variants of the roman faces, but independent imitations of handwriting without much dynamism.

Fig. 4:  Dynamic skewing

Curvature range discussed in my previous column is directly related to dynamism, too. In most cases, expanding the curvature range leads to adding more explicit dynamism to the shape, as we go from a perfectly still and symmetric circle with its zero curvature range to expressive Beziers, and further on to the forms made of straight lines and sharp corners (e.g. triangles and arrowheads) - which, indeed, represent nothing but the ultimate case of infinite curvature range. In the world of textures, dynamism is most often expressed by various blur themes, notably by the "wind" and "motion blur" texturizing effects. Indeed, anything moving swiftly enough appears blurred to the human eye, and imitating that blur by design means is a sure way to add dynamic flavor to the composition. This effect is especially useful in that it is capable of dynamizing abstract shapes or letters of text in a quite realistic (to be precise, photographic) manner.

Fig. 5:  Dynamic texturizing

Asymmetry of any kind, be it in the aspect of form, size, or color, is another source of dynamic implication (Fig. 6). In fact, what is called asymmetry is a single object version of what we call contrast for a couple of objects; much as contrast is perceived as such only when the objects are visually linked and not just dissimilar, asymmetry may only produce any effect when we get the feeling that the shape could be symmetric but isn't. Dynamic eye flows induced by pairs of contrasting objects are the subject of a next section.

Fig. 6:  Dynamic asymmetry

Now, imagine that all of the features listed above do not apply, and what we have is a simple, perfectly symmetric shape without any slant, rotation, or blur. Even in this case some traces of dynamism are present in the object, and it's easy to see that its inclination to move mostly depends on the object's proportions (Fig. 7) - in other words, on whether its height is close to its width, or the dimensions differ considerably. Simply put, a stretched rectangle is more likely to imply some dynamism than a square.

Fig. 7:  Dynamic proportions