LG has — finally — moved to on-screen buttons with the LG G2, giving up the ghost (for now) on the capacitive buttons of old. That provides for some flexibility for how things work in addition to making things a little easier on the hardware side.
By default, you've got three buttons — back, home and menu. Yes, an on-screen menu button. Not recent apps.
You do get the option to move things around a little bit, as well as add a fourth button, which either can be a shortcut to QuickMemo, or it can quickly pull down the notification shade. (As for multitasking, you can "slide" between apps with a three-finger gesture as part of something LG calls "Slide Aside.")
As the image above shows, you've got the following permutations:
Interesting and confounding at the same time.