Here’s a look at the evolution of the Dock and how to change back and forth between a 2D and 3D appearance using Terminal or the third-party cDock utility.

The Evolution of the Dock

OS X Cheetah introduced the Dock, creating the Mac desktop’s distinctive look. It was a basic 2D dock with the original Aqua pinstripe interface elements introduced in the first OS X version. The Dock morphed a bit through Puma, Jaguar, Panther, and Tiger, but remained 2D. With the advent of OS X Leopard, the Dock underwent a dramatic change with a three-dimensional, reflective look. The Dock icons looked like they were standing up on a ledge. The 3D look continued through Snow Leopard, Lion, Mountain Lion, and Mavericks. However, with OS X Yosemite came the return of the flat, two-dimensional Dock, which remained through subsequent releases.

Use Terminal to Apply a 2D Effect to the Dock

Use Terminal with OS X Leopard, Snow Leopard, Lion, Mountain Lion, and Mavericks Docks that are currently sporting a 3D look.

Use Terminal to Switch Back to a 3D Dock Effect

Use this Terminal trick with OS X Leopard, Snow Leopard, Lion, Mountain Lion, and Mavericks Docks that currently sport a 2D look. defaults write com.apple.dock no-glass -boolean YES killall Dock exit

Use cDock to Change the 2D or 3D Dock Aspect

A third-party app called cDock changes the 2D or 3D aspect of your Dock and provides other customizations, including transparency controls, custom indicators, icon shadow, reflections, and more. defaults write com.apple.dock no-glass -boolean NO killall Dock exit If you have OS X Yosemite, installing and using cDock is a simple process. For OS X El Capitan through macOS Big Sur, installing cDock requires an extra step that involves disabling your SIP (System Integrity Protection). This security measure prevents potentially malicious software from modifying protected resources on your Mac. While cDock is by no means malicious, the SIP security system prevents cDock’s Dock-modification methods. Disabling the SIP system isn’t recommended just to perform cosmetic Dock changes. If you choose to go ahead with the process, cDock includes instructions for how to disable SIP.

How to Use cDock

Here’s how to change your Dock’s appearance using cDock: csrutil enable Press Return, quit Terminal, and restart your Mac.