The original source for this puzzle was the 2013 MIT Mystery Hunt:<p><a href="http:&#x2F;&#x2F;www.mit.edu&#x2F;~puzzle&#x2F;2013&#x2F;coinheist.com&#x2F;rubik&#x2F;a_regular_crossword&#x2F;index.html" rel="nofollow">http:&#x2F;&#x2F;www.mit.edu&#x2F;~puzzle&#x2F;2013&#x2F;coinheist.com&#x2F;rubik&#x2F;a_regula...</a>