Title Text:Spacetime Soccer, known outside the United States as ‘4D Football’ is a now-defunct sport. Infamous for referee decisions hinging on inconsistent definitions of simultaneity, it is also known for the disappearance of many top players during… [more] Origin:https://xkcd.com/2705/ https://www.explainxkcd.com/wiki/index.php/2705:_Spacetime_Soccer…