Now things get more interesting! We humans love to see shapes.
A good shape is one which is longer than it is wide.
It often has a diagonal orientation.
And it has incidents ("jig-jags", if you will) unequally distributed along the edges.
Any shape which will fill a circle or a square or a triangle with two equal sides is probably a shape that can be made more interesting.
A good shape is often fairly large and occupies an off-center location in the painting.
BORING BETTER INTERESTING
"Artists are symbol collectors, shape makers and entertainers!" - Edgar A. Whitney, World Famous Art Instructor