Admittedly, “art” may be, ah, stretching it a bit, but hot-pulling scrap styrene model sprue over an open flame to make plastic rods of various thicknesses is a classic technique in plastic model-building. The resulting material can be as thin as a human hair, and commonly finds use in scale modelling as antenna aerials, wire, bolt heads, etc.

Flame-stretching is only the first of four creative reuses for leftover sprue from Peter Hall of Scale Model Guide, who also favors them for paint stirrers, internal bracing members, and temporary mounts for small parts during sculpting or painting.