a^2 + b^2 = c^2

Since shark fins are triangular in shape, why not make a shark entirely out of triangles?

 Cut from cardboard. I forgot how difficult it is to create sharp points when cutting out cardboard.

I planned to do a shadow of a shark by making a cut-out similar to this, but rather with just one large shadow. Might as well put this one to use and do a reverse shark shadow! Two birds, one stone.