When I was a young boy, I spent hours, even days, playing with erector sets, which consisted of little metal beams, nuts, and bolts (and later, pulleys, gears, and small electric motors). Basically, you could construct anything your mind came up with, tear it apart, and create something new and completely different. And you didn’t have to make something stationery — with the little motors, you could create things like windmills or planes. I’ve built automobiles, towers, homes, and more.