An intriguing and educational display structure appears to be spinning upon itself without any apparent drive mechanism, power supply or bearing. The software components include a control object component and a user interface component. A first portion of the biasing member is then disposed against a second stem portion of the valve member, the second stem portion being opposite the first stem portion. A tension generated by a restoring force of the wing portions fixes the PCB with the mold frame without using a separate fixing member. The connecting plate is fixedly supported on the sliding members.