Click on the ball to pick up; drag and release to throw. The playfield is mostly protected with glass - only a few select regions are bare, in which you can pick up and manipulate the ball.

The inspiration for this was several different of toys I knew when I was young - in particular, a mechanical game where two players squirt air into a water-filled playfield to push a plastic ball through their goal ring, in mimickry of basketball. And, of course, there's a bit of Windosill in this.