The Layperson’s Bible: In Which God Prohibits Spandex

"Thou shalt not wear a garment of divers sorts, as of woolen and linen together." (Deuteronomy 22:11)

That’s right. Blended fabrics are prohibited. God must have foreseen the invention of polyester, and tried to head it off, but thou art a stiff-necked people. Don’t feel too bad, though, because apparently only some Native American Indian tribes (and perhaps some cowboys) were getting it right, anyhow:

"Thou shalt make thee fringes upon the four quarters of thy vesture, wherewith thou coverest thyself." (Deuteronomy 22:12)