Your problem is the way they are cut. A layer cake is a grouping of 10in squares and your pattern will call for the use of those squares maybe other squares cut from them. A jelly roll is a grouping of strips usually 40 of them only 2.5inch x the width of fabric 41-44 inches long. your pattern will call for strips of varying lengths not a squares.
You will either have to turn your layer cakes into strips by cutting them into 2.5" strips then sewing them end to end or. The opposite and sew your strips into sets and cut them into the proper save squares. Either will create a lot extra work and waste.
Last edited by Billi; 04-05-2014 at 01:55 PM.