Better sprinkler arcs

The circles are confusing for heads that aren’t throwing full circle. It’d be nice to have an arc that just showed where the head is throwing. Some kind of a dynamic block maybe.

We’re working on that one. Dynamic blocks are tricky. Here’s what we’ve got so far.

The problem is when the drawing is opened again after the blocks are inserted, they look funny and don’t behave as they should till the dynamic block is opened in the block editor and saved.