Glad you reviewed this great app! One week after buying this app I was helping a friend hauling stuff on his truck. The "Trucker's hitch knot" came in handy and it was the first time I ever made such a knot. Just used my iPhone and did it! A sales guy in the lumber yard saw the knot and thought I do this for a living.
It's a very handy and well made app. For $.99 it's a steal, because at some time, you'll need it.