# Sacred Number

30 gnoMons ways of growing Aristotle observed that some things suffer no change other than magnitude when they grow. He was describing the principle the Greeks referred to as gnomonic growth. Originally a term for a carpenters tool, a gnomon is defined as any figure, which, when added to another figure, leaves the resultant figure similar to the original. The contemplation of the gnomon leads to an under standing of one of natures most common principles, growth by accretion. The more permanent bodily tissues, such as bones, teeth, horns, and shells all develop in this way. The ancients had a general fascination with patterns and progressions created by wholenumber ratios. Examples are Platos Lambdoma, which produces the full range of musical ratios, and the proportional rectangles used in Greek design where each subsequent rectangle is built on the diagonal of the previous one. The Fibonacci sequence is a more recent discovery, but relies on the same principle of gnomonic growth. The drawing below shows a cutaway cross section of the Aztec temple of Tenayuca, revealing five gnomic reconstructions, made every 52 years, when their calendar, inherited from the Mayans, was reset and all buildings renewed. 31