Ugh! It’s baaaack. That little 3-D mechanical puzzle invented in 1974 is just as frustrating (and rewarding) as ever. Today, over 350 million Rubik’s cubes have been sold worldwide to authentic and wannabe geniuses everywhere. Already solved it? Then you deserve the shirt below. Haven’t figured it out yet but plan to keep trying? Put one on for good luck and think positively. Just think it looks cool? Whatever your reason is for loving this best-selling puzzle, you’re not alone.