OS X and elementary OS share incredibly similar core design and usability ideals, but elementary is no mere rehash of OS X. They challenge a number of things people take for granted in OS X, such as double-clicking[0] and minimise[1], but they're obviously not afraid to borrow things that OS X does well.

[0] http://elementaryos.org/journal/we-moved-cheese

[1] http://elementaryos.org/journal/whats-still-window-controls