Topology puzzle in 3 levels

thingiverse

I believe that this design is topologically equivalent to The Staggering Stair Step Puzzle, so I've called it a remix. The three versions can each be printed in one piece without support structure. A separate loop of string is needed, which I made by fusing the ends of a length of plastic cord in a small gas flame. The loop must be long enough to thread through the various rings - about 250mm circumference for level 2. The aim of the puzzle is to finish with the loop of string around only the shortest rod, as in the picture. If the loop is already on the shortest rod the aim is to detach it. No force or bending of the printed structure is required.