Today I was asked by a Boy Scout if I had a sharpener on me. I didn't, but explained to him that I drove one up to the camp (Trask in Monrovia CA). He and another member went with me to the parking lot where I promptly rolled down my car window and used the edge to bring his knife back to shaving sharp in under a minute. The boys were impressed. There was a group of Cub Scout parents and scouts watching as well. The parents were dumbfounded. I explained how and why it worked. There will be interesting activities in a few driveways tonight