So, what we've seen here is that when interfaces help people distribute cognition, it can encourage experimentation like we saw in Tetris; it can scaffold learning and reduce errors, like we saw with the Montessori blocks; it can show only the differences that matter, like in the London Underground map; it can convert slow calculation in the fast perception, like we saw with the map coloring; it can support chunking, especially by experts, as we saw with chess, and with gestural interfaces; it can increase efficiency as we saw with diagrammatic representations; and it can facilitate collaboration like we saw in the cockpit. 