Professor Uwe Meffert, the German world cube inventor, takes a picture with children each holding a Pyraminx on Saturday, his 80th birthday, in Shenzhen. Professor Meffert invented the Pyraminx in 1970 and then developed other versions, including the Megaminx, Skewb and Skewb Diamond. He hosted a cube competition for teenagers at his birthday party.  Wei Jiancheng