The object of this quiz is to adjust each circle's diameter so it splits the circle's population as evenly as possible. When you click Start you will be shown a marker on a random US census tract (there are over 80K census tracts in the US). Also you will see an circle between 200 and 500 miles radius. Adjust the diameter by rotating it using the endpoints, trying to split the halves into equal populations. Then click submit. You are scored on how close you have split the circle into 50% population in each half. Circle population is tallied by totaling all census tracts (small census areas of average 4K population) within that circle.
NOTE - population in Canada and Mexico is NOT counted at all, only US population within the circle.
Quiz Takers 
The advanced level needs to be updated, since Eugene is now larger than Salem, Roy is bigger than Syracuse, and Herriman is bigger than Eagle Mountain. It says it was last updated in 2015, 11 YEARS AGO!
The quiz was always live – I changed that now so it states that. And now of those population comparisons is true, according to most recent estimates on citypopulation.de.
When I ended an untimed int quiz, the results never displayed and I was left instead with the message “Calculating stats…”
I’ll take a look and see if I can figure out the issue.
What is supposed to go into the Alabama Square on Beginner? Its neither Birmingham nor Atlanta, Montgomery, Mobile, Tallahassee, Auburn, Tuscaloosa, Hoover, Huntsville, Pensacola….???
it’s Huntsville. just worked for me.
I hate Alaska!
Personally… I enjoy obscure, barren wasteland.