Inspired by a similar map published earlier this year and meant to help visualize the segregation of Chicago’s neighborhoods, dot-happy data explorer Eric Fischer has now produced similar maps for 102 U.S. cities. Here’s his map of Houston — which we’ve taken the liberty of darkening a bit to make patterns more apparent. The maps are based on ripe old data from the 2000 Census, the dots colored according to the racial and ethnic categories provided by respondents. Each red dot represents 25 White people, each blue dot 25 African Americans, each green one 25 Asians, each orange one 25 people identifying themselves as Hispanic. “Others” are rendered in gray.