You can now try ClusterStorm before you buy it. Get the free version here. Also available for iPad is Glowmation, a simple neon, doodling app that traces over your original drawing using animated particle effects. Get Glowmation here.

The free version of ClusterStorm ends at predefined pill counts, but you can replay arcade over and over getting a higher score until you're ready to go further in the full version. Ready more about ClusterStorm Free here.

Glowmation is a free app with an in-app purchase that allows you to upgrade to the full version which includes more colors and the ability to load/save a drawing. Read more about Glowmation here.