We found a load of polystyrene in the garage this afternoon, so we decided to make a [hot-wire cutter](http://en.wikipedia.org/wiki/Hot-wire_foam_cutter) for it. Basically, you take some wire with an ohm or two resistance and pass a few amps of current through it. The wire is held tight and the polystyrene melts as it passes around the wire.
Musings, parallel thoughts