Right you are Ritzy, how lucky am I? I wrote and asked him about it and here is his reply:
"The program I used is called Illustrator from Adobe, its expensive and very good but the learning curve is maybe a bit steep. This seems to be the best free equivalent
http://inkscape.org/ the important thing is to establish a scale when you open the document the rest of it is practice, quite boring unless you have a creative goal in mind."
So for the computer clever among you there you have it, I think if I tried I would never get this quilt done! So Rita, I am sorry this is not a free programme included with your Mac but perhaps this information may be useful to you. Good Luck.