PhysicsWeb is running an article by one of the researchers who has developed the theory that the universe may be finite, rather small, and soccer-ball shaped. The question is still open; it's one theory that fits cosmic microwave data from the Wilkinson Microwave Anisotropy Probe (WMAP). Apparently testing the theory by looking in the indicated way through the WMAP data would so far be computationally prohibitive. From the article: "The Poincaré dodecahedral space can be described as the interior of a 'sphere' made from 12 slightly curved pentagons. However, there is one big difference between this shape and a football [soccer ball] because when one goes out from a pentagonal face, one immediately comes back inside the ball from the opposite face after a 36 degree rotation. Such a multiply connected space can therefore generate multiple images of the same object, such as a planet or a photon. Other such well-proportioned, spherical spaces that fit the WMAP data are the tetrahedron and the octahedron."