Don’t Try This With Full Pint Glasses
Four glasses are placed upside down in the four corners of a square
You wish to turn them all up. You may do so by grasping any two glasses and, optionally, turning either over.
There are two catches:
1. you are blindfolded
2. the table is spun after each time you move the glasses
Assuming that a bell rings when you have all the glasses up, how do you do it?