Concentration Grid is a web/mobile device app implementation of the mental skills exercise used by athletic coaches and sports performance/psychology professionals for student-athletes (typically with pen/paper and stopwatch) . Concentration Grid provides convenient gameplay/replay and records time/performance data and history (the app also integrates sharing of results on social media). Concentration grids of between 3 and 14 rows/columns can be generated – and used for training/practice, skills conditioning and intra-squad competition. (The mental focus grid exercise is particularly popular with baseball and softball coaches.) Concentration Grid provides a fun competitive challenge for students, athletes, coaches, trainers, teachers, parents – young and old. Challenge yourself.