I have some sort of wasting disease where I'm awake for three-four hours then asleep for an equal period. So here's a little something from my Poor Wife's Reward/Diversion lesson plan file:
There are no circles.
The tabletops are the same size.
The horizontal lines are straight and run parallel to the top of the frame.
(My wife claims not to see these.)
The vertical lines are straight. It's the figures in front that are crooked.