The Mac’s Dock has undergone revisions over time. It started out as a basic 2D Dock that was flat and slightly translucent, then morphed into a 3D look with Leopard. With OS X Yosemite, the Dock returned to a 2D look. If you’ve grown fond of the 3D look and want to experience it in OS X Yosemite or later, or if you have an OS with the 3D look and prefer the 2D look, it is possible to switch between the two Dock looks.

Below you can see the evolution of the Dock and how you can switch between a 2D and 3D view using Terminal or the external utility cDock.

OS X Cheetah introduced the Dock, which established the signature look of the Mac desktop. It was a simple 2D dock with the original Aqua pinstripe UI elements introduced in the first version of OS X. The Dock changed a bit through Puma, Jaguar, Panther, and Tiger, but remained 2D.

With the arrival of OS X Leopard, the Dock underwent a dramatic change, taking on a three-dimensional, reflective look. Dock icons now looked as if they were standing on a ledge. The 3D look was retained in Snow Leopard, Lion, Mountain Lion, and Mavericks. However, OS X Yosemite saw the return of the flat, two-dimensional Dock, which remained in subsequent releases.