When I was growing up mucking about with my own hair - I was obsessed with three main things - curls, making my hair look longer and making my hair look shorter. I guess it was all about making my hair different to what it actually was. So a nice quick and easy method to gain an instant bob - no scissors involved - this would be excellent for an instant Snow White hair style. So you take you hair and brush it out as smooth as possible. Then pop an elastic around the hair right down near the bottom - it is best if you can try and place it so all the hair is caught - that's why Hettie's is up a bit - to catch in the shorter pieces. You can experiment here - where the elastic is determines the length of the bob. Next you thread a ribbon through the elastic and pull it till it is half way through - I delved into my circa 1986 stash of lace for this particular piece LOL.
Then simply hold each end of your ribbon and pull it up to tie it like a head band. In doing so poke the elastic up under so that it is all hidden. Tie your bow and then play with the hair to get it sitting nicely - you can even give it a gentle brush. If you want your style to hold, I'd give it a little spray with some hairspray or your fav product - and voila - an instant bob!