equilateral
what are the three internal angles of an equilateral triangle? well, 60 degrees of course, because they are also equiangular, with all three internal angles congruent to each other, and by definition adding up to 180 degrees. i know this is a hard sell, but math is really so much easier than art.
atlas cedar pinecones
Are they that shape naturally? They would make perfect xmas tree ornaments!