What does Exodus 28:16 say in the KJV?

Foursquare it shall be being doubled; a span shall be the length thereof, and a span shall be the breadth thereof.

A description of the high priest's breastplate.

King James Version (public domain)

Traditionally attributed to Moses · c. 13th century BC · The Pentateuch — Genesis, Exodus, Leviticus, Numbers, and Deuteronomy — is traditionally attributed to him

Context

14And two chains of pure gold at the ends; of wreathen work shalt thou make them, and fasten the wreathen chains to the ouches.

15And thou shalt make the breastplate of judgment with cunning work; after the work of the ephod thou shalt make it; of gold, of blue, and of purple, and of scarlet, and of fine twined linen, shalt thou make it.

16Foursquare it shall be being doubled; a span shall be the length thereof, and a span shall be the breadth thereof.

17And thou shalt set in it settings of stones, even four rows of stones: the first row shall be a sardius, a topaz, and a carbuncle: this shall be the first row.

18And the second row shall be an emerald, a sapphire, and a diamond.