Software to Navigate OS with Keyboard?

I read about an app that allows the user to navigate their OS with keyboard. It isn't tab-based (pressing tab moves through menus etc), and it isn't controlling the mouse with keys. Instead, it divides the screen into sections, and pressing a key puts the mouse in a section. I think the section then subdivides into more sections, and pressing a key moves into one of those sections, etc, until your mouse is on the button or input you want. And it's supposed to be super-fast.

Anyway, I've tried googling for it but can only find tab-based nav or controlling the mouse with a keyboard. Any ideas?