Concave polygon Concave polygon A simple polygon that is not convex is called concave, non-convex or reentrant. A concave polygon will always have at least one reflex interior angle—that is, an angle with a measure that is between 180 degrees and 360 degrees exclusive. Some lines containing interior points of a concave polygon intersect its boundary at more than two points. Some diagonals of a concave polygon lie partly or wholly outside the polygon. Some sidelines of a concave polygon fail to divide the plane into two half-planes one of which entirely contains the polygon. None of these three statements holds for
180 Degrees South: Conquerors of the Useless "Chris Malloy's film strikes so deeply into the heart of Patagonia's wilderness we come to feel at home there". 180 Degrees South: Conquerors of the Useless 180 Degrees South: Conquerors of the Useless, or simply "180° South", is a 2010 documentary directed by Chris Malloy that covers the journey of Jeff Johnson as he travels from Ventura, California to Patagonia, Chile retracing the 1968 trip that Yvon Chouinard and Doug Tompkins took in their Ford E-Series Econoline Van. After finding footage of the 1968 expedition, Johnson decided to make climbing the Corcovado Volcano in Patagonia as his life goal and,