3D eraser animation

Howdy!  An exercise we did at school yesterday which is animating an inanimate object.  A bit of fun and it's nice to just concentrate on the animation.  This was done in 2 hours from scratch.  Luckily the model didn't have to be awesome, just practicing timing and continuing to get used to animating with rigs, controllers and graph editors.  It's an odd feeling jumping between 2D and 3D animation programs.  It's like switching brains...