The development of Super Mario Bros. is an early example of specialization in the video game industry, made possible and necessary by the Famicom's arcade-capable hardware. Miyamoto designed the game world and led a team of seven programmers and artists who turned his ideas into code, sprites, music, and sound effects.[24] Developers of previous hit games joined the team in February 1985, importing many special programming techniques, features, and design refinements such as these: "Donkey Kong's slopes, lifts, conveyor belts, and ladders; Donkey Kong Jr.'s ropes, logs and springs; and Mario Bros.'s enemy attacks, enemy movement, frozen platforms and POW Blocks".[25][26]