That is mighty tight. If your FQs are out of square or a little short it won't work at all. The diagram is definitely wrong, since it assumes you can cut 8.5"+8.5"+4.5" (=21.5") from a piece that is clearly marked as 21". I wonder if it's an older pattern, written when fabric tended to be a little wider. I'm working on a quilt now from Blanche Young's book, Tradition with a Twist. I have found that her calculations assume that you can get more than 40" usable WOF. Fortunately I did my own calculations before starting, and I have plenty of the fabrics, but it would be very disappointing if I relied on her numbers and came up short. I'm glad you figured out how to make it work.

Glad you were able to figure it all out!

This is what I came up with, assuming your FQ is accurate.

I have purchassed fat quarters that were only 17.5 inches long.

As I said, theoretically, it should work. In actuality, I would not bet my life on being able to get those cuts from some of the ( unwashed) fat quarters that I have purchased.

this pattern doesn't allow for any wiggle room - the cuts require 17.5 by 20.5 fabric and your FQs probably weren't that size. All the other advice above, like issues that result from washing, or "out of square" FQs will result in you not being able to get the cuts you need.

I worked it out like Evie did. Cut the 2 long ones they way they say, that leaves a 13" strip, then cut an 8 1/2" strip and subcut into 2 1/2", then that leaves a 4 1/2" strip to subcut to 2.5"

Sure glad you were able to figure it out.....

I would either buy a yard or two of fabric and let it fill in for the missing fabric, wherever it happens to fall in the design. You could either use a complementary blender or a contrasting fabric to make those pieces "pop". This is what we quilters call a 'design decision'. Don't let it make you crazy or frustrated, just pour a glass of wine and make that quilt YOURS! Remember to post pictures. Lol!

Lol! Thank you for the smile! I will definitely update with pics of the quilt.