alpha shapes - "Imagine a huge mass of ice-cream making up the space ℝ3 and containing the points as 'hard' chocolate pieces. Using one of these sphere-formed ice-cream spoons we carve out all parts of the ice-cream block we can reach without bumping into chocolate pieces, thereby even carving out holes in the inside (e.g. parts not reachable by simply moving the spoon from the outside)."
Island disputes in Asia: Territorial conflicts about islands, islets and reefs have intensified in the past few months. Here is a look at some of the places where the question of national sovereignty is raising tensions. Via Washington Post.