Cut a 3 inch by 3 inch square log about 6 to 8 inchess long from the center of the watermelon by cutting off the sides and ends of the watermelon to create such a shape. (Use the unused watermelon for slice and snack or puree flesh for a drink.)

Slice the log into 3/4 inch thick squares. Cut the squares diagonally to form right triangles.

Puree the blueberries. Spread the blueberry puree on a serving platter imitating a pond or lake. Sprinkle the cereal around the edge of the blueberry puree like sand or pebbles at the "water's" edge. Float the triangles of watermelon upright on a short side like sailboats on the water moving in the same direction. Serve immediately.

Source:

Watermelon.org