The first thought was about basketball nets. I saw an advert on the sides of several Rocesvalles shops that depicted a person playing basketball.
Create hyper realist paintings or maybe stickers. Maybe actual photographs done to scale of things from learning; basketball backboards, water fountains, doorways, fire alarms, clocks, bell, blackboards, etc. print these out to size and then apply in odd locations, altering the reality of the world via illusion.