Tesseract Day - June 8
Today is a day to celebrate perhaps the best known 4 dimensional object, the tesseract . As the cube is to the square, the tesseract is to the cube. While a cube consists entirely of 6 identical squares arranged in 3 dimensions, the tesseract consists of 8 identical cubes arranged in 4 dimensions. Since we see in 3 dimensions we have difficulties imagining 4 dimensional objects, but mathematics works just fine in higher dimensions even if most of us aren't intuitively comfortable there. Tesseracts and similar 4 dimensional objects are relatively new; the 19th century mathematician Ludwig Schläfli was one of the first to write about them. User:JasonHise, Public domain, via Wikimedia Commons