Gobos are small round metal cutouts that once placed in a holder can be inserted down inside the Lekos. We should have one gobo lying around somewhere that is used as a leaf cutout. It breaks up the light coming out of the leko into a bunch of the leaf shaped things to give you interesting effects for specials. If you can't find the holders, they might already be in the light, just with no gobo in them, they go in at about the same point as the four shutters.