I don't have the ruler, but I know how to make a fish block using a triangle in a square. It's basically a 4 patch, 2 plain squares, one is the water color (blue), and the other is the fish body color (white). the other 2 squares are the squared triangles, with the main large triangle the water color, and the 2 narrow pieces are the fish color. This block has to be set on point. Make the squares any size you want.
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