This borer is similar to Seminole patchwork. If you google that you will see more examples and tips. When you have a string of strips like this they tend to curl and it is difficult to get a straight cut for any distance. To help with this I use painters tape and tape the end of the strip to the cutting mat. This way I can tug on the strip a bit to get it more straight. I also only line up my ruler for a few inches and trim that part then line up the next few inches and trim. Another thing that help immensely is to starch your fabric before you cut your initial strips. Starch really helps stabilize things