Costa's genus 1 three-ended minimal surface is described as a torus with three points missing -- I.e., three points have been removed from three-dimensional space and flung to infinity. Just how is this done? How do you turn a simple donut into Costa's genus 1 three-ended minimal surface? Here's how!
See also: demonstrations.wolfram.com/TheTopologyOfCostasMinimalSurface at the Wolfram Demonstrations Project