Cut a slit down the middle of the front of the paper bag. Cut a large circle in the bottom of the bag to form the neck opening. Cut a large hole on each side for the arms. Draw squares, triangles, stripes, etc., on the sack with markers.
Darker colors work best.
Use crayons or markers to fill in the designs. After the coat is colored, you can punch holes in the front where the slit is and string yarn for ties.