Nosey about LOOP? Well, its name is not just because it spells pool backwards.

The idea came from a real loop. A loop of string. When you put a loop of string around two pins, or focus points, a pencil will draw out an ellipse. 

The ellipse has many fascinating properties and only some of them are best illustrated by the medium of indoor sports.

Here's why. Every point on the curve makes the same angle to each focus point. 

So in an elliptical pool table a ball from one focus will always rebound towards the other one. There are therefore three indirect ways of hitting a ball into the pocket of LOOP.

The object of LOOP is to win by potting a colour ball and then the black ball.

The starting position is illustrated above: the black ball is on the dot, with a red and a yellow on either side. The cue ball is positioned anywhere on the line between the black and the pocket. 

The first player names a colour that he wants to pot and the first shot must hit that colour.

The other player must aim to pocket the other colour.

The game proceeds like pool, with each player taking alternate shots until the first person has potted their colour and the black. A player who pots the black with his or her colour still on the table loses the game.

The key to winning at LOOP is always to calculate the angles by considering the positions of the focus points.