Letter element can be used to combine Email, Mailbox, Mailman, Newspaper, Pigeon, Post Office, Sack, and Smoke Signal. Making Letter is complicated, and we have figured out the easiest way, you need only 23 steps starting from the basic elements. You need to make Life, Human, Stone, Tool, Wood, and Paper first. Check out the detailed walkthrough and try it yourself.
Fire + Earth = Lava
Lava + Earth = Volcano
Water + Water = Puddle
Water + Puddle = Pond
Water + Pond = Lake
Lake + Lake = Sea
Earth + Sea = Primordial Soup
Volcano + Primordial Soup = Life
Earth + Life = Soil
Life + Soil = Plant
Earth + Water = Mud
Air + Air = Pressure
Earth + Pressure = Stone
Air + Stone = Sand
Sand + Mud = Clay
Clay + Life = Human
Human + Stone = Tool
Big + Plant = Tree
Tree + Tool = Wood
Fire + Wood = Charcoal
Charcoal + Wood = Pencil
Wood + Water = Paper
Paper + Pencil = Letter