Let's play a game of four-square. I've got a ball...here, see?
It's a rubber band ball. Took forever to make. Very colorful.
I'll start as king, in the King's square: "Open".
Do we have three other people?
I bounce the ball in front of me, to the square labeled "Hidden."
Now that's silly, where'd the player go?
I bounce the ball to the corner, in the square labeled "Unknown."
Where did the ball go?
I bounce the ball to my left, to the square labeled "Blind".
The game continues, but the ball never returns to my square.