http://www.slate.com/blogs/the_vault/2013/06/28/voting_rights_and_the_supreme_court_the_impossible_literacy_test_louisiana.html
Jim Crow laws put in place to put barriers up to minority voting in the South. They had ten minutes to complete and weren't allowed one wrong answer. Had to pass this to be allowed to vote.
Can't believe this was allowed to happen as recently as the 60s.