A device receives a control system model that includes a fixed portion that models elements of a control system to be controlled and a tunable portion that models elements of the control system used to control the elements modeled by the fixed portion. The first connector can releasably connect to a plurality of portions of a second connector disposed on an edge of another display device. This structure allows the formation of a high performance light-emitting element with high luminous efficiency and long lifetime. The motor may be controlled by signals from a throttle embedded in the surfboard and which may be hand controlled by a rider of the surfboard.