I've been building geometrical objects from various materials, and these pages at pendred.net show them off. Some of these structures are quite interesting. An easy way to discover more about them is to build them.

The dimensions and ratios that crop up are always worth trying to find out precisely because they are often much simpler than you would think, even when they are irrational.

* Contact: lawrence@pendred.net

The sand pyramid has a perfectly square horizontal base and is not noticeably lopsided. You try doing that with your bare hands and no spade. ( I did however use a stick for measuring out a circle, then a diameter, then a square )

Erosion adds to the aesthetic qualities.