A few nights ago I fancied drawing something. So I decided on an old fretsaw machine I still have, which I think is from the 1970's.
Instead of the more usual motor driven saw, this uses an electromagnet. The spring steel at the top of the arm keeps the blade under tension. The electromagnet pulls down the 'vibration plate' (I call it that because I don't know the correct name), then releases. It continues the cycle until switched off.