This graded course gives a select group of students who have excelled in a Problem Solving Initiative (PSI) class the chance to spend another semester, under faculty supervision, working on the subject matter of that PSI class. The course is designed to give students a more in-depth problem solving experience at a higher level of sophistication than may have been possible during their original PSI classes. Students may only enroll following PSI faculty invitation. Faculty and invited students determine the number of credits to be awarded.