A convertible toy includes a body portion and a base selectively coupled to the body portion. The image forming apparatus further includes multiple developer containing members disposed in the main body for providing the corresponding imaging units with developer, the developer containing members being arranged in a direction extending from the operation side of the main body. In another embodiment, a portion of the second semiconductor material is replaced with a third semiconductor material in order to impart uniaxial strain to the lattice structure of the second semiconductor material.