A colorful, interactive poster serves as a portal to the realm of dimension, with destinations ranging from Flatland to hyperspace. Meet authors Madeleine L’Engle (A Wrinkle in Time), E.A. Abbott (Flatland), and Michio Kaku (Hyperspace). Ponder Penrose tilings, gravitational lenses, and tic-tac-toe on a torus. Play with geometric shapes. This fascinating Web site was originally created for this year’s Math Awareness Month (April).