Order-2 apeirogonal tiling
In geometry, an order-2 apeirogonal tiling, apeirogonal dihedron, or infinite dihedron is a tessellation of the plane consisting of two apeirogons. It may be considered an improper regular tiling of the Euclidean plane, with Schläfli symbol Two apeirogons joined along all their edges can completely fill the entire plane, as an apeirogon is infinite in size and has an interior angle of 180°, which is half of a full 360°.