Thicket

You get water, earth, fire and air. Drag one onto another and see what it makes. There are six hundred and fifty five things to find and every one of them can be reached from those four, which is a claim the build checks rather than a claim I am making.

Drag something across from the left, then drop it on something else.

Drag a thing off the rail onto the board, and drop it on another to combine them · or click one on the board and then click a second, which does the same · drag a thing off the board to get rid of it · / jumps to the search, Esc clears it · the group buttons filter the rail, and a filled corner marks a thing nothing else is made from · Hint shows one pair worth trying, once every forty seconds · Undo takes back a clear or a combine · F for fullscreen