A roundabout. There used to be daily wrecks in one area where a high traffic road kept turning on a high traffic back road, and people would get into fender benders, turning too soon, and even deadly wrecks. The roundabout cut down on the speed and less stopping to wait. The wrecks are fewer and less damage.
Learning with activities. I can remember how to do something by doing it with someone there watching me while I ask questions if I'm doing it correctly.