1. For the body, cut off each foot of two matching knee socks, as shown in Diagram 1, to make two tubes; save the foot pieces. Cut up the long side of each tube to create two flat pieces.
2. Cut one sock from the contrasting pair in the same manner to make a flat piece for the belly. Pin the contrast belly pattern, as shown in Diagram 2, on the right side of the flat piece; cut the piece out.
3. Pin the belly piece with its pattern on top to the top cut edge of one body piece (the sock ribbing will be at the bottom edge); baste together. Satin-stitch the raw edge of the belly piece to the body; tear off pattern.
4. Cut one of the sock feet from Diagram 1 open so the heel is centered in the flat piece, as shown in Diagram 3a; this will be the face. Cut the matching sock foot from Diagram 1 so the heel is cut open, as shown in Diagram 3b; this will be the back of the head.
5. Pin the face piece to the top of the body-belly piece with right sides together. Sew the pieces together; open and lay the sewn piece flat to create the monkey front, as shown in Diagram 4. Using embroidery floss and the tapestry needle, stitch a running-stitch smile onto the contrasting heel to make a snout. Leave the stitches a bit loose to allow stretching when the head is stuffed.
6. Pin the head back piece to the top of the remaining body piece with right sides together, as shown in Diagram 5. Sew together. Open and lay the piece flat for the monkey back.
7. Using the ear pattern, cut four ear pieces from black socks. Pin and sew two pieces together around the curved edge. Turn right side out; pinch the straight edge and baste to make one ear. Repeat to make a second ear.
8. Pin the head pattern to the head front piece, aligning neck seams. Position ears on face sides, with right sides together; baste. Remove pattern.
9. Turn one of the remaining knee socks inside out. Flatten and smooth it out as shown in Diagram 6; pin layers together. Using contrasting thread, baste two lines down the sock as shown by the dashed lines on the diagram. Machine-stitch over the basted lines; cut between the lines of stitching to create one leg and one arm piece. Turn the pieces right side out. Stuff with fiberfill. Repeat with matching sock for a second leg and arm set. Position arms on body front with right sides together; baste.
10. With right sides together, position the front and back body pieces together, aligning the neck seams and sandwiching arms between layers. Pin the head pattern to the head front, aligning the bottom of the pattern piece to the neck seam. Baste together, as shown in Diagram 7. Machine-stitch over the basted lines. Clip the seam allowance around the curved head edge. Turn right side out; stuff with fiberfill.
11. Baste legs to the inside back of the body through the bottom opening. Hand-stitch the body closed. Using the patterns, cut eyes, cheeks, and a nose from desired colors of felt. Stitch two French knots for nostrils. Use fabric glue to adhere felt face pieces. If desired, add a purchased hat or crown.