Tank treads? How?

Solution 1:

If you are referring to this build showcased in one of the menu screens:

'Muntjak' Heavy Exploration Crawler (Vanilla)

Then according to the description it reads:

I tried using tracks like wheels, with a traditional steering, powered by pistons, because rotors were too weak, and it's working surprisingly well. Each track is suspended by the pistons, and can pivot, so lots of traction is granted, meaning that it can climb rather well.

so it appears to be a large mechanism built out of other vanilla blocks like pistons.

On a personal advice note, due to the... let's just say 'slightly temperamental' (So buggy it has become a godlike entity in the community) physics engine, any such vehicle is not practical for even close to reasonable speeds, most constructions in the menu bg have a slightly false nature in that they are all very prone to destruction as well as aren't practical. Some even require experimental mode to function properly, a mode which is disabled by default for its instability. They mostly serve to show the theoretical potential of the game at its best.