Tesseract

Listen! This sentence's period - that's me. I'll just move one inch to my right, you see. ------>. Now, I trace a one-inch segment of a line. It's my one-dimensional redesign. Watch me trace my line segment down from there, producing what some folks might call a square. I execute this little trick for you in a special dimension known as two. Look! I rise off the page, one inch - mutually perpendicular, a sinch! Orthogonal to left/right and up/down, I'm a cube, a 3D shape of renown. A fourth perpendicular direction, and my shape should warrant your attention; and the name they call me, to be exact, is Mister Hypercube or Tesseract.