Monday, February 16, 2009

Quilt Math - Algorithms for Cornerstones and Sashes

I've always found it annoying to have to figure out the number of cornerstones and sashes in my quilts. I'll forget the (usually very odd) numbers, and have to figure them out again, usually by drawing a picture of my quilt and counting. Argh! I was sure that there had to be simple algorithms that covers this, so I asked my math whiz hubby to figure them out. Here are his results: (Note: I always put cornerstones and sashing around all blocks, even the ones on the outer edges of the quilt.)

For a quilt that has n by m blocks, where n is the # row blocks and m is the # column blocks:

The number of cornerstones = (n+1)(m+1)
The number of sashes required = (n+1)m + (m+1)n

So for my Country Chain and Knot quilt, which has 4 rows and 5 columns of blocks:
n=4 and m=5

The # of cornerstones = (4+1)(5+1) = 5x6 = 30 cornerstones
And the # of sashes = (4+1)5 + (5+1)4 = 5x5 + 6x4 = 25+24 = 49 sashes.

Cool! Thanks, Larry!


Linda B. said...

I can't find your e-mail address, so I am responding here. LOVE your site, especially the bachelor buttons on the heading! My husband always picked those for me when we were dating. When I told the florist I wanted them in my bouquet, she told me that was inappropriate. I asked if I called them cornflower, would she use them? Jeesh, I could have just gone out in the woods and had a hippie wedding.

Anyhow, alpacas are not that much work until they start birthing. Then I watch them ALL the time. I will not let them suffer. Most of the time they have easy deliveries, but there are the difficult ones, and I help.

Barb said...

Oh my head is reelling..and I am like you, I would just draw a picture and count...probably still will...

Snoodles said...

THANK YOU!! I knew there had to be a way to figure this out without counting every time!! Kudos to your math whiz hubby!!

Chookyblue...... said...

I have saved this to my I can use it at a later date......