So I needed to be able to draw a spiral on a big round tablecloth to begin the piece I am working on. Being quite lazy and unwilling to get out my geometry book I chose the easy way out. I tied a piece of cord around my spray starch can, attached that cord to a chalk marker and spiralled away. I experimented a little before I chose the starch can, tried a pencil (spiral too tight), a dye pot (spiral too loose) and ended up with the spray starch can (spiral just right). I taped the can to the middle of my piece, started the chalk marker cord stretched tight at the edge of the tablecloth and then just walked around the circle as the cord wound around the can. Voila! a Spiral!
Whew! That was a potential close encounter with my geometry book.