A tessellation with fishes (Escher).

Author:
ltgrau
We construct a tessellation with fishes, by means of simple geometric transformations. From a square, we draw a fish and are able to cover the plane without any gaps or overlaps.
Move the sliders in order to perform the construction. When the three green sliders are completed, we have the first fish. Then, we begin to cover the plain with the rest of the sliders. Which transformations are involved in this tessellation?