Most were made when I was a child. The first was a power stealer that used radio waves to power an LED. The second was a large wooden glider around 5 feet long and wide. The third was a pair of glasses for reading while walking using a half-silvered mirror and a magnifying class to project miniaturized mirror-reversed book pages into my eye so I could read while walking between classes in college. The fourth was a studying shack I made while in grad school (which I commuted to, so I needed a private space for dedicated study time).