It ain't the prettiest, being made from a random pile of old Legos, but it is functional.
There's no frets and it tends to get out of tune easily due to the loosening of the blocks so it is difficult to play, but it sure is fun to be able to make music with some plastic blocks and nylon string.
Now just to prove that it works, here's me messing up the best song you can play on 2 strings (sadly this was the best of 4 takes)