Exodus 27:13-16

On the east end, toward the sunrise, the courtyard shall also be fifty cubits wide. Curtains fifteen cubits long are to be on one side of the entrance, with three posts and three bases, and curtains fifteen cubits long are to be on the other side, with three posts and three bases. “For the entrance to the courtyard, provide a curtain twenty cubits long, of blue, purple and scarlet yarn and finely twisted linen—the work of an embroiderer—with four posts and four bases.