What to do:

Slice the watermelon in half, and then make an even slice to achieve a circular piece for the base of your popsicles. Make sure the circular piece of watermelon is 1-2” thick.
Using a small knife, carve out the watermelon flesh from the circular piece. Make sure to not break or cut the rind. Set the rind aside for later use.
Place the carved watermelon flesh, 1 1/2 cups of frozen strawberries and 1 cup of plain, nonfat Greek yogurt in a blender. Blend until smooth.
Place the outer edge of your melon on a parchment paper lined on a baking pan or tray (and make sure the tray fits your freezer). Using a knife, cut slits in the side of the rind for popsicle sticks and place popsicle sticks evenly around the rind. (The more popsicle sticks you used, the smaller cuts you can make. For this recipe, you should be able to make about 4-5 popsicle sticks.)
Carefully pour the watermelon strawberry mixture in the center, and top with berries or fruits of your choice. (Your kid can help by scooping out the watermelon flesh and adding toppings.)
Freeze overnight or until frozen.