Starting in 1981 programmers looking for credit and royalties on sales began leaving both APh and Mattel Electronics to create Intellivision cartridges for third-party publishers. They helped form Imagic in 1981 and in 1982 others joined Activision and Atari. Cheshire Engineering was formed by a few senior APh programmers including David Rolfe (author of the Exec) and Tom Loughry, who had created one of the most popular Intellivision games ""; Cheshire created Intellivision games for Activision. Third-party developers Activision, Imagic, and Coleco started producing Intellivision cartridges in 1982, and Atari, Parker Brothers, Sega, and Interphase followed in 1983. The third-party developers, not having legal access to Exec knowledge, often bypassed the Exec framework to create smooth 30 Hz and 60 Hz Intellivision games such as "The Dreadnaught Factor". Cheaper ROM prices also allowed for larger games as 8K, 12K, and then 16K cartridges became common. The first Mattel Electronics Intellivision game to run at 60 Hz was "Masters of the Universe" in 1983. Marketing dubbed the term "Super Graphics" on the game's packaging and marketing.