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 of so many ecological horror documentaries on topics ranging from global warming to the corn syrup in our peanut butter." He writes "The regard for the planet shown in "180° South" comes from the quiet, philosophical nature of the people profiled in the film, who realize there is more adventure in the preservation of nature than in its conquering." "Minneapolis Star-Tribune" praised the film by writing "If you are this close to chucking it all in, packing your bags and going vagabond, by all means do not see "180° South." Director Chris Malloy's eco-tourist documentary could stoke your wanderlust to