Expanding Tyson’s Corner: Wow. There’s been a lot of regional planning news lately. First, local leaders met at a local planning gathering equipped with Lego blocks and maps trying to figure out how to accommodate 2 million more people in the area in the next 25 years. Second, the Post reports on how Tyson’s Corner Center (where we snagged this image) is seeking to expand, transforming its regional shopping mall cluster into a giant built-up…