In this figure, the CRC is illustrated using two connected rectangles. The first rectangle, on the left, is labeled "D: Data bits to be sent." The rectangle on the right, slightly smaller, is labeled "R: CRC bits." The left rectangle is designated as being comprised of d bits, while the right rectangle is comprised of r bits. These two rectangles are identified as the Bit Pattern. Below them is the mathematical formula, given here as: D o 2r XOR R