I posted this in
this forum post by ofnuts, but thought I would also post it separately. Inspired by the video linked to in the post by ofnuts, I attempted to do one of the animation effects in that video using Gimp and GAP:
The whole animation is based on each of the three colored pencils being animated to move up and down and then just adjusting the frame of the animation each pencil starts at. However, it's a bit more complex than that for achieving a sine wave effect. It took me about three or four hours to look at the animation in the video, plan it out, work through errors, render it, make additional changes and again render it to achieve the final results.
It would be interesting to try some of the other effects in that video.
Thank you for checking this out.