It is all in the cutting... you have to measure TWO sides before cutting to make sure both of those TWO sides are on a level mark of the ruler... then cut... you won't have a bend in your material at all.... the fold is one place where the ruler has to be level with and the other is the 2 AND A HALF MARK on the ruler going the same way you are wanting to cut... before starting you have to cut the end of the material straight first by having the fold on one of the marks at the end of the ruler or else the end of the ruler must be on the fold.. from then on just cut your strips whatever size you need... but the tutor told me to level everything up every now and again to cut the end of the material straight as it does alter... it shouldn't but it does... and then keep on cutting...it pays to take a class on bargello or else get a book with bargello in it.