This rather unsophisticated calculator will tell you the number of stitches to cast on
and the number of rows to work if you give it a sample size (in inches or centimetres)
and a desired width/length (in the same units). It assumes the width is the number of
stitches and the length the number of rows.
There is no error checking - please put only numbers in the boxes.
The result comes as an alert message.