[help] What would you use for the 'foot' of a platform leg to allow it to sit on a sloped floor.

So i see these little thingies on various tables and chairs - what looks like a sort of ball joint with a little platform.

The legs of my platform will likely be 4x4, so I need something a little bigger.

Rather than measuring and surveying the floor, I'd like to build something a little more versatile. I'm not sure what these would even be called to start googling.

UPDATE: LEVELING FEET!

Submitted February 20, 2015 at 09:18PM by cat5inthecradle http://ift.tt/19JRj60