Why is the sail shaped like a pyramid with a flat top?
In times gone by, ships were rigged with versions of square sails. There were almost always at least 3 on a mast, and so they formed this general overall shape as a group. Square-riggers were more directional (with the wind) sailing vessels. They relied on the trade winds a lot back then, able to go where the winds would take them mostly. This sail shape and location will allow the urn to move in a fashion that looks normal, and in a predictable direction.
