The Symmetric Yantra (Figure 1) is a fairly simple geometric figure, and thus comparatively easy to draw with a pencil, compass and ruler.
The Shri Yantra (Figure 2), on the other hand, is actually a cleverly drawn visual sleight-of-hand! It is an ancient illusion that is a precursor to similar 20th century perceptual illusions, in the same class of figures as those produced by the gestalt
psychologists. Like the famous 'duck-rabbit' diagram, or the portrait of the 'young-woman/old-woman' (left), it demonstrates that we can be tricked by perception when the figure-ground relationship in a picture is reversed or otherwise tampered with.
As in these other cases, the illusion that is deliberately built into the Shri Yantra
makes it very difficult to draw, as you no doubt come to realize if, in fact, you did try to reproduce it with a pencil, ruler and compass. In order to achieve the intended effect one must keep in mind two goals that pull in different directions, just as in trying to draw the portrait of the young woman/old woman, you would have to keep in mind that every line you make is a line in two completely different portraits!
© J. Fudjack