Hyperbolic Quilt by Helaman Ferguson.
This unruly quilt, made up of regular pentagons stitched together so that four pentagons meet at each corner, will not lie flat. It can be thought of as a piece of the hyperbolic plane, an infinite, two-dimensional mathematical surface.
Wearing a hyperbolic poncho at Helaman Ferguson's exhibit at the 2009 Joint Mathematics Meetings in Washington, D.C. Photo by H. Ferguson.
Photo by I. Peterson