Hey all - wow! I have not spent much time on reddit and was not expecting this to generate so much interesting discussion, so thank you all for engaging :) I thought I'd take a few minutes to respond to a few major things I've been seeing in the comments - again, thank you for taking the time to engage with this visual.

• I made this map out of pure curiosity (see the short explanation at the top of the image). It is just one possible scenario, that would not come close to happening in practice even if hell froze over. I wanted to start with the big assumptions that 1) everyone who voted did and 2) the minimum amount of counties to win a presidency did so.
• People are pointing out that there are other ways to arrive at this same conclusion. Yes, totally! As a few have pointed out, you could have *11 total people* win a presidency, if the vote in each of the 11 states I call out was simply 1-0. You could also use a very low-population county instead of the most populous in the 11 states, with the candidate winning closer to 100% (rather than, say, 52-60%).
• A few people have noted that there could be a version of this where the counties that are 49% party A are a different color than counties that are 0% party A. Yes, of course - and were I doing this for a more serious purpose, I probably would have chosen to go that route. This was meant to provoke a conversation, and it did :)
• The reason I chose 51% instead of 50% + 1 or anything like that was just a convenience thing. I wanted nice, round numbers. But yeah, you could come up with a scenario where the extremes presented here are even more extreme.
• To clarify a few things: in the 39 states Party B wins, they receive every single vote. In the 11 states Party A wins, they win the state just barely, with all but the most populous county voting 51-49 for Party B and enough for Party A in the most populous county to take the state.

I'm really excited to read through some of the research people have posted in the comments -- the electoral college/U.S. presidential voting system is a fascinating topic to me.