At first, things looked great
But then, everything went wrong because jigsaw blades are flexible, and the pressure, bent the blade in a bit due to the centrifugal motion. So... my circle was ruined - see below
That was frustrating. Had to go to the store, buy more wood, glue it, clamp it, etc. That cost me two days of work. But again, sunshine, breeze, tools, noise, sawdust = not bad!
I realized a MUCH smarter move than a jigsaw would be a router. Router bits don't bend. I put the router on a piece of thin MDF, and used the same technique of swinging it around a central point like a drafting compass. This worked wonderfully well.