Designed 1x1x2 Rubix Cube. You will need a small M3 screw to join the two blocks. Part-C is pushed into Part-A which locks and freely rotates. The other end is pushed into Part-B and M3 is screwed from back of Part-B. Check for rotation of the two blocks- if too tight- loosen the screw, if too loose- tighten the screw. When satisfied with the friction...insert Part-4(One time insert).