Pictured is a Logic Works simulation of the 4-bit x 4-bit multiplier circuit. The circuit contains inputs a3, a2, a1, a0, b3, b2, b1, b0, four sum-in's, and four carry-in's. The outputs of the 4-bit x 4-bit multiplier are p7, p6, p5, p4, p3, p2, p1, and p0.