Controlling and modifying light is a lot of what photography with studio lights and battery powered strobes are about. Especially when it comes to portraits, I like to work with my lighting setups so they add something that is not perfect or flat.
Twisting and turning your lights to make use of the edges is one very effective way of doing that. Breaking up the light with a scrim, gobo or something else is also very rewarding.
This DIY project is all about a cheap prism from a LED Disco Party Bulb that I found for under 10 EUR/USD.