Well, you need certain conditions in order for it to be most effective. And sometimes it won't work.... But you'll know if it won't, generally. Thats why. Its not great but sometimes its cool. The paper cup version is the most sure fire and leaves the most freedom for what environment you can do it in. And in my opinion its the coolest. If you wanna get it, its only 14 bucks, but don't expect to do it all the time or even often. I wouldn't put it in a show. But you can have occasional fun with it.