Rjukan, a factory town in a deep Norwegian valley, gets no direct sunlight from roughly autumn to spring; the mountains to the south are simply in the way. In 1913 Sam Eyde, the industrialist who built the town, suggested putting a mirror up on the mountainside to send some of the sun back down. It was never built. In 1928 his company built a cable car instead, so people could ride up out of the shadow and stand in the light for a while. Then in 2013, a century after the first idea, a local artist got the mirrors built: three panels on the slope, turned by computer to follow the sun, throwing a bright patch onto the town square. Between them the two answers cover the only two options there are. You can take the people to the light, or bring a piece of the light to the people. What I like is that Rjukan did both, eighty-five years apart, and kept the first one running when the second arrived.