I tried to teach myself to quilt many years ago and wanting to do it on the cheap just in case it wasn't my thing, I bought a small rotary cutter and a plastic ruler that wasn't for quilting. Well, when I did one of my first cuts the cutter jumped over the small ruler edge and got the index finger on my left hand. It took a long time for it to heal and I can see still the "vacant" spot where it took the chunk of flesh! It was about 7 years before I bought the Omnigrid ruler and was successful in learning to quilt and about being careful with those very, very sharp rotary cutters!