A lacrosse passing drill.
There are four lines (A,B,C and D), each at a point on a square. Player A starts with the lacrosse ball and runs toward player B. Player B runs toward line C (perpendicularly to player A's movement) and receives the ball from player A. Player B continues with the ball as player C moves toward line D. Player B passes to player C, who advances toward line D. The lacrosse ball continues to be passed around the square.
Add more than one ball
Make the square smaller for tighter, faster passing