The fifth major revision (mid 2007) shared the same form as the previous model, but was thinner and used anodized aluminum and a glass panel over the entire front. The third and fourth major revisions, the iMac G5 and the Intel iMac respectively, placed all the components immediately behind the display, creating a slim unified design that tilts only up and down on a simple metal base. The second major revision, the iMac G4, moved the design to a hemispherical base containing all the main components and an LCD monitor on a freely moving arm attached to it. In its original form, the iMac G3 had a gumdrop or egg-shaped look, with a CRT monitor, mainly enclosed by a colored, translucent plastic case, which was refreshed early on with a sleeker design notable for its slot-loaded optical drive. It has been the primary part of Apple's consumer desktop offerings since its debut in August 1998, and has evolved through seven distinct forms. IMac is a family of all-in-one Macintosh desktop computers designed and built by Apple Inc. macOS (Previously known as Mac OS X, OS X).
