The corners of each block could be a pop of colour . thinking out loud here . the solid black lines could be black/white prints . just a vision that popped into my head. I like it in just black grey and white too
Music center for preschool playground. Spray paint pots and pans and hang them along the fence. Let the students explore with different "drum sticks." They could make music with their hands, hard sticks, or soft covered sticks.