A geoboard is a mathematical manipulative often used to explore basic concepts in plane geometry such as perimeter, area or the characteristics of triangles and other polygons. Consisting of a physical board with twenty-five raised pegs in a symmetrical square five-by-five array, students are encouraged to place rubber bands around the pegs to model various geometric concepts or to solve other mathematical puzzles. Two-dimensional represenations of the geoboard may be applied to ordinary paper using rubber stamps or special "geoboard paper" with diagrams of geoboards may be used to help capture a student's explanations of the concept they have discovered or illustrated on the geoboard.
