The Yak plays an important role for the Tibetans; it is a source of food, clothing, fuel and travel. Butter is turned into Godly art during the 15th of January. The Tibetans create sculptures and lanterns out of Yak's milk for an annual festival in Lhasa. Preparation takes place months ahead when the butter is hand made and painted into flowers and religious figures that can reach several feet in height.
I came across this piece of information while reading Fat by Jennifer McLagan.