A hierarchical taxonomy of quadrilaterals is illustrated by the figure to the right. Source: Internet
All non-self-crossing quadrilaterals tile the plane by repeated rotation around the midpoints of their edges. Source: Internet
Because the Saturn used quadrilaterals, rather than standard triangles, as its basic polygon, cross platform games had to be completely rewritten to see a Saturn port. Source: Internet
Concave quadrilaterals In a concave quadrilateral, one interior angle is bigger than 180° and one of the two diagonals lies outside the quadrilateral. Source: Internet
Determining congruence of polygons The orange and green quadrilaterals are congruent; the blue is not congruent to them. Source: Internet
Convex quadrilaterals Euler diagram of some types of simple quadrilaterals. Source: Internet