Williams' first solid-state machines produced in 1976 were prototype runs based on electromechanical games; "Aztec" (1976) and "Grand Prix". Williams continued to release new electromechanical pinball machines through October 1977, when they released their last, "Wild Card". From November 1977, Williams released solid-state pinball games exclusively, beginning with their first solid state production model "Hot Tip" (1977), which sold 4,903 units (the electromechanical version previously released in June sold 1,300 units). From the late 1970s through the 1980s, Williams released numerous innovative pinball games, such as "Gorgar" (1979, the first pinball featuring a synthetic voice), "Firepower" (1980), "Black Knight" (1980, the first featuring multiple levels), "Jungle Lord" (1981), "Space Shuttle" (1984), "Comet" (1985), "High Speed" (1986), "Pin*Bot" (1986), "F-14 Tomcat" (1987), "Cyclone" (1988), and "Taxi" (1988).