Rill Marble Shooter

A spring high on the slate feeds a little stone rill, and someone has set a run of glass marbles rolling down the dry groove beside it. The brass turret is there to make sure none of them reach the drain.

Marble shooter: fire glass marbles from a brass turret into a chain rolling toward a drain. Three of a colour pop and the gap snaps shut.

A chain of glass marbles rolls along a groove cut in slate, from a spring toward a drain. The brass turret in the middle fires the marble in its mouth wherever you point: drag and the turret follows your finger, let go to fire, or simply tap where you want the marble to go. The dotted guide shows where it will land, with the chain's roll counted in. A marble joins the chain where it strikes; three or more touching marbles of one colour pop. The part of the chain ahead of the pop snaps back to close the gap, and if the two colours that meet match and make three, they pop too, as a chain. Every pop pushes the whole chain back from the drain. A shot that pops nothing stays in the chain and makes it longer. Tap the turret to swap the marble in its mouth with the one in its back socket. Pop every marble to clear the level; if a marble reaches the drain, the level is lost.