Just prior to Kathy and I traveling to Washington DC, I had been reading a very interesting book about Hugh Everett's "Many-Worlds" interpretation of quantum mechanics. One of the concepts the reader has to wrap his or her head around is that of the existence of a multiverse, where there isn't a single universe but instead an infinite number of them which are constantly splitting. One where you ate breakfast in the morning and one where you didn't, one where you posted a photo of an interesting art installation and one where you didn't and on and on. Anyway, there are many Smithsonian art museums but on the National Mall there are two that have a walkway between them which is located below ground level. At some point a very interesting art exhibit called "multiverse" was installed. It consists of thousands of LED lights that race around making patterns that are really compelling. You can walk the length of this tunnel or ride on one of two moving sidewalk conveyor belt thingies like the two guys in the photo are doing.