Wash the blackberries, puree them with the water and the agave syrup in a mixer (smoothie program). Fill glasses with one third each. Clean the blender jug.
Wash the raspberries, puree them with the water and the grenadine syrup in a blender (smoothie program). Spread over the blackberry puree. Clean the blender jug.
Puree the honeydew melon pulp in a blender (smoothie program), place on the raspberries.
If you want it to go fast, it tastes of course also if you puree all ingredients together, it just doesn't look so pretty then.