Here is a picture of our solution in various different formats.
The following two are probably the best for displaying on a screen. png is a free version of gif.
(Don't ask me why the larger picture is the smaller file.)
The following three are best for printing out as they are in resolution-independent formats. pdf is likely to work if you use Windows and postscript is likely to work if you use a version of Unix or have a postscript printer.
And these are non-antialiased black-and-white png files which you could use for printing
if the above formats fail (and your browser can do the appropriate conversion).
Can you spot the parallelogram in the solution?
