My first attempt at ASCII art, hope it's better than my early life attempts 
at ka-ka painting.

            /J\ --- yes, a hook, on yer bus
           /   \
          /     \ -- rope
         /  .    \
support /         \[=] --- filler cap, from your favorite bag 'o wine
 bar-- |===========| |        stitch into the plastic/vinyl etc.
       |             |
       |             |
       |             | --- about 18" square, stitched solidly together
       |             |     canvas swells tightly shut when wet, thus the 
need to 
       |             |     presoak it for 24 hrs.
       |_____________|
       |o___________o| ---  some sort of tie down at corners keeps it from   
                          flipping onto your hood, err... windshield?

holds maybe 1 1/2 gal.

that's all folks, tim s.