The monochord zither or diddley bow is one of the oldest instruments around. Almost every culture has their own version with a resonator made from whatever hollow item was on hand. It is usually played with a glass or metal slide to change the pitch, with the string being either plucked with a finger or pick, or struck with a stick. You could also bow it I guess, although I’ve never tried.
To quote One String Willie:
“A diddley bow is slide guitar stripped down to its most elemental level.”
Mine are made from a variety of small boxes. Each is unique: the hardware varies by my stock of parts at the time, as does the wood neck…sometimes round, sometimes square. The neck can be varnished, or painted. Let me know if you have any colour preferences.