willferg

Here's my take on it. When you sew all your strips together, you have one row deep (2.5", or 2" finished) by however many inches long based on however many strips you use (40 strips at approximately 40" each is 1600 inches, hence the name). So you have a strip that is 2" x 1600". When you fold it in half and stitch the next long seam, you will now have two rows deep – 4" – and 800" long (half of 1600). After the next seam you sew, your 4" will double to 8", and your 800" will drop to 400". Then 8" goes to 16" and 400" drops to 200", then 16" goes to 32" and 200" drops to 100", and one more fold and you have 64" by 50". This is approximate only because your strips may have been 41" or 42" or you might have used spacer blocks between strips. However, the 64" depth should be constant; I'm not sure how you could end up with anything different...

sandyquilts

Someone worked out all those measurements. Go to http://exuberantcolor.blogspot.com/2011/07/jelly-roll-race-aka-random-plank-quilt.html

Quilt Fan

Hello:
Thanks to all of you for the input. The math solution should have come to mind but to be honest I thought it would be better to ask. And it was because of the other information given. Think I will give the question to dgd who is a math whiz. Happy, healthy, prosperous New Year to each of you.