ProFoto Spot Small
The Spot Small optical attachment from Profoto is a handy way to create theatrical and other interesting effects with your flash. Although optimized for D1 flash heads the Spot Small will work on any Profoto head with certain limitations on modeling lights. The focusing attachment comes with a gobo holder that accepts the huge range of 2.6" diameter gobos from companies like Rosco that allows you to project abstract patterns, leaves, windows and blinds, just to name a few, on your background.
The Spot Small has a projection range of 3.28' - 9.8' and will give you image diameters of 1.54' @ 3.28' to 4.9' @ 9.8'. You can use modeling lights up to 500W with fan-cooled flash heads but no more than 15W with heads without fans.