If you squint hard enough, the capital letter pi (Π) looks like half a circle.
https://discuss.tchncs.de/post/896490
If you squint hard enough, the capital letter pi (Π) looks like half a circle. - tchncs
Maybe this is why pi was chosen for half of the circumference of a circle.
If you don’t squint, it looks like a table. Maybe whoever chose it hadn’t had lunch yet.