Ponder This is a monthly problem that lets ambitious people "match wits with some of the best minds in IBM Research." The problem is usually fairly abstract and requires refined mathematical skills, critical thinking, and patience to solve. Each month a new problem and the solution for the previous month are posted online. Users are encouraged to submit their answers for possible recognition on the website. Visitors to the Ponder This website can browse previous problems and solutions dating back to May 1998.