Little Alchemy is a free game that allows you to combine elements or formulas to make new elements, such as mud, rain, plant, bread, and water. There are about 560 elements in the game, and you could mix elements to create interesting, fun and surprising items. Every combination is a little puzzle to solve.
Fire + Air = Energy
Water + Earth = Mud
Air + Water = Rain
Earth + Rain = Plant
Plant + Mud = Swamp
Swamp + Energy = Life
Earth + Life = Human