Norman and I pondered as to what to use for a template to determine the circle shape for the skylight opening in the dome of the chamber we we5e building. It needed to be an18 inch diameter. We looked around the house keeping cottage
We considered a pizza dish. It was too small. The portal in the washing machine looked the perfect size. It had glass in it too and could be used as well for the top of the tumulus.
We ended up using Mrs Howarth's laundry hamper instead.
It worked perfectly.
New technology and materials meets old.