What's with all the squares on the map?

Great information in this article
http://www.nytimes.com/interactive/projects/cp/summer-of-science-2015/latest/jefferson-grid?smid=fb-nytimes&smtyp=pay&smvar=mapkwp&ad-keywords=SocialRem&kwp_0=39942&kwp_4=230245&kwp_1=185497


Check out the Jefferson Grid
http://goo.gl/XmdVbq