if your pattern calls for a jelly roll it probably uses 40" strips of fabric--- a layer cake is 10" squares so will not work for a jelly roll pattern- unless the jelly rolls are cut into strips 10" or less ... yardage ... 4 layer cake squares X 3 layer cake squares = 12 squares (40" x 30") jelly rolls are 40" long (or width of fabric-sometimes 42"- 44") by 2 1/2" so, 14 strips = width of fabric x 35"