"That's true, but then again there are a lot of opportunities to use that diagonal motion from the back of the board, and oftentimes, people don't think about the square color before moving a piece with a rigid moveset. Well, like the knight..."

He picked up a knight and moved it in it's characteristic L shape.

"That's how the Knight moves - You can see easily how if I move it here, it could be captured by a bishop placed here, or here, or here..."

He demonstrated each move in turn, three times attacking his own poor knight, and from places well away from where it had been placed to begin with.