Amish Diamond Quilt (afghan)

A few weeks ago I went to Pennsylvania and had a side trip to Lancaster.  While I was wandering around, I came across the Lancaster Quilt and Textile Museum.  If you're ever in the area, I would really recommend stopping by.  I'm not a huge quilt fan but I did see a quilt that fascinated me.  It was one of the earliest of the Amish patterns, from what I understand, called the Center Diamond Quilt and all I could see was how easy it would be to knit.

This is a (poorly blocked) sampler I did just to work out the dimensions and to show the basic elements.  The center diamond is knitted from tip to tip, casting on 2 stitches and increasing each side every other row until you have the desired number of stitches (in this case 20).  Then you simply decrease each side every other row until you have 2 stitches left.  Bind off. 

The brown sections were picked up from each side of the diamond.  I wasn't too sure about how many stitches to pick up since geometry has never been my strong suit but I discovered that I needed to pick up 75% of the width of the diamond (plus one to make an even number).  In this case, the widest part of the diamond was 20 stitches so I picked up 16 stitches along each side.  I decreased stitches on each side every other row to finish up the square.

With the square finished, I picked up 24 stitches across the top (12 for each triangle - 75 % of  the 16 stitches I picked up for the section).  I knitted in garter stitch until I had 5 ridges and then did a stretchy bind off.  I did the same for the bottom then basically the same thing for each side except the pick of stitches included picking up stitches across the blue bar of the top and bottom.  And, as they say, whala.

The theory is that you could use the formula above to make it any size you want.  As you can see from the link above, there's all sorts of variations that can happen within this basic recipe.  I think what I would do for my large version is to make the center diamond and brown sections a seed stitch and then garter for the outside borders.  That way it could easily be reversible.  One thing I like about having the center diamond in stockinette is that it kind of pops out but I don't know that it would have the same effect in real size.  You could include some sort of motif in the middle of the diamond and on each of the diamond corners.  That could be cool.  I think I would like this sample more if I'd had a 3rd color for the outside border.