If you ever wanted finer control over your Etch-A-Sketch lines, then you may want to consider splicing in a NES controller! Here's the process as described by Alpinedelta32, the creator of this brilliant mod:
I connected the etch-a-sketch knobs to stepper motors, which are then controlled by an Arduino microcontroller. The Arduino program I wrote takes signals from the NES controller and sends them as stepper motor control instructions.
Low tech toys meets high tech mod, this is what geeks do with their toys when they grow up!