The US Map of Prices of Pot

UPDATE: just got the question on Twitter: "what does this have to do with development?" Answer: nothing, except that you will never understand development if you are so quick to ask that question. When I first saw this map, I immediately thought legalize pot! what a great teaching tool for my Intro students! So students, please explain using the concepts of supply, demand, and transport costs (including in this case smuggling costs) the pattern of prices you see here.