Any quadrilateral

tiles the plane. The tiling is formed by rotating

by 180° about the midpoints of its sides. The same process is then applied to the four new quadrilaterals, and so on.
Another approach is to use the parallelogram

formed by joining the midpoints of

's adjacent sides. Tile the plane with

in the obvious way. Translate the parts of

from the copies of

adjacent to

across

into the opposite copy of

. Then copy the three different patterns in the copies of

to form the same tiling as before.