When we compare the simpler decorative designs made use of by the less cultivated races of men, we find that there are certain distinct and opposed tendencies the predominance of which is of importance in helping us to explain the origin of the design. The tendency to make straight lines and rectilinear angles, which we may call the "rectilinear habit," is found in work executed on hard stone by a graving tool, and in work where square-cut stones are set together or flat pieces of wood or straw are interlaced, and in coarser kinds of weaving, bead-work, and basketwork. The opposite tendency is found in work executed with a brush and fluid paint on pottery or cloth, or even with a graver on soft clay or bone. The contrast is well shown in the two renderings of one and the same "pattern," shown in A and B of Fig. 49. A is the rectilinear angular decorative design which is known as the "Greek key pattern," whilst the scroll below it is the "curvilinear" treatment of the same subject. The first takes its rectilinear character from a structure built up of hard blocklike pieces; the other is the flowing, easily moving line of a brush laying on paint, or of a style moving over clay or soft wax. The contrast is the same as that of the capital letters of the Roman alphabet, as used in print, with their equivalents in "copper-plate," cursive handwriting. [Illustration: FIG. 49.–The Greek Key pattern in _A_ rectangular, and _B_ curvilinear or "current" form.] Another pair of tendencies opposed to each other which have much significance in the explanation of decorative design is the tendency to convert the simple lines of an original design into a drawing representing some animal or plant shape. At the end of the last chapter I distinguished this as the "naturalizing" tendency, contrasting it with the grammatizing or simplifying tendency. A good example of it is seen in Fig. 50. In A of that figure we see a circle divided into three cones by curved lines; this is a known design. It is called a "triskelion" (meaning a three-legged figure), or is more correctly termed "a three-branched scroll." The curves are converted into angles and straight lines in B, and then the stiff rectilinear "triskelion" is subsequently developed into three human legs, as shown in C, Fig. 50. It is naturalized. Were the change to proceed in the other way from the three human legs to the simple lines, we should have an example of the opposed tendency, namely, that of converting drawings of natural objects–by a degenerative or reducing process–to the simplest lines representative of them. This tendency, which we call "grammatizing" (from gramma, the Greek for a line), is far commoner in early art than the naturalizing tendency which sets in when the artist is exuberant, self-confident, and imaginative. We see a "naturalizing" tendency in the flamboyant and arabesque decorative work of the renascence, but it is also found among the happy Minoan, or Ægæan, island folk