Originally Posted by WorldWind
Lay the box on your rack with a corner at your seat post the opposite corner straight back. Put the hook on one end of a bungee down through the cardboard top at the edge just where you can see the front of the rack emerge from under the box. Wrap down and around and around and when tight the other end goes through the lid in the other side of the box. A second bungee hooks to the back of the rack under the box, up and over the trailing corner and back down to the back of the rack.
--- Eighteen responses but this one was the FIRST answer.
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"The bicycle is the perfect transducer to match man's metabolic energy to the impedance of locomotion. Equipped with this tool, man outstrips the efficiency of not only all machines but all other animals as well." Ivan Illich ('Energy and Equity')1974