When you get into animation school you gotta animate, no way around that. Here are a few that I did in the first 3 weeks of school.
Starting off with bouncing ball, bowling ball, balloon and pendulum to study momentum in movement. Decent exercises to get started, but not particularly paper-friendly. Around 250 sheets used.
Some are poor quality since not all the linetest cameras are the same quality, but for the purpose of just linetesting they're good enough.
