Peel and trim both ends of the banana. Cut the middle part into 1-inch tall cylinders. Cut watermelon into 1-inch thick slices, a little bigger than banana if possible. (Use a cookie cutter for round shapes. Place banana cylinders on a serving plate, leaving 1-inch space between them. Use the bigger end of a chopstick to press a hole in the center of each watermelon slice. Put the watermelon on top of banana, then put a blueberry in the center of the watermelon. (Optional) garnish with strawberry slices.