The New York Times has just published a very nice visualization (or "Sankey diagram"; thanks for the reminder, Len DeGroot) about how state-by-state voting has evolved since 1952. It was designed by Shan Carter and Mike Bostock, two visual journalists I'd recommend you to follow closely. When I first saw the graphic —half an hour ago, and really quickly— I was enthralled. I wrote so on Twitter. A few minutes later, Chrys Wu, someone whose opinions I deeply respect, replied with a sound…