Two pivot points, and a length of cord twice as long as the distance between them, attached at both ends to the pivots. Pull the cord tight at a angle to the pivot line. Keep doing this over a range of angles, and the pivots become the focii of an ellipse. Wanted to try that in the sand, but ran out of time.
Ever seen any ellipses?
Officially, I said "out back" There's open space beyond our yard, the lions were caught about 40 feet past our property line. Most of the grass there has already been pressed down by stange creatures in the middle of the night. (That's where the deer sleep.)
I'm pleased you'll take these ideas to your group for discussion. I hope they try the techniques themselves to see just how easy it is. Especially the two person method, which I've not tried, but am convinced will work.
Off Topic » in reply to re: On Topophilia and sparklers.
Elliptical formations