I really enjoyed that book! This pair of pants actually looks fairly complicated. If you look at the knees, they're a different patter of twill than the upper

I really enjoyed that book! This pair of pants actually looks fairly complicated. If you look at the knees, they're a different patter of twill than the upper and lower leg. This could possibly be made so that the knee flexes more easily and is more durable. The seat reinforcements are interesting as the article points out. You commonly see a smaller version of this added to jeans worn by people who commute on their bikes.