Irregular Monomorphic Tilings

You might think that it was impossible to tile the plane with a completely irregular figure. In fact, in the case of quadrilaterals, the exact reverse is the case. ANY irregular or regular quadrilateral will tile the plane! Yes - even concave ones! (The proof is quite straightforward - just remember that the interior angles of a quadrilateral add up to 360°)

And since two irregular triangles can be placed together to make a quadrilateral, the same is true of triangles as well!