Here are some more of the secret details of Mormon garments. Before 1990, the Mormon endowment ceremony promised a penalty for revealing the sacred details: your throat would be cut, your breast torn open, and you'd be disembowelled.
The garments are sacred, embroidered long underwear to be worn at all times, except when bathing, swimming, or on a doctor's visit. Garments must not be cut, sewn, or altered in any way, but when they wear out, you can cut out the sacred embroidered symbols and burn them - then the rest of the underwear can be disposed of however you wish.
The sacred signs are reminiscent of Freemason symbols: over the right breast is a buttonhole which resembles a mason's square, like a backward L; over the left breast is a compass, a mark like a capital V. Sewn into the abdomen and over the right knee is another marking which looks like a horizontal buttonhole. These symbols stand for various phrases said in the Mormon endowment ceremony.
Garments are usually white, but also come in olive drab to match the U.S. military uniforms.
Some Mormons believe that the garments actually protect them from evil and harm. They are said to represent the garments given to Adam and Eve when they were kicked out of Eden.