Snail Trails

Month six of the Sweet Land of Liberty quilt features four Snail Tails blocks finishing at six inches.  I've never done this block and so I googled it under "6 inch Snail trail quilt block".  Absolutely nothing came up.  I tried "Snail Trail quilt block" and got lots of hits although nothing that was 6 inches.  I decided on a 12.5" unfinished block pattern and figured that I could just halve the sizes.  I did so and if the sizes were over a half inch, I increased to the next inch....so 2.75 became three inches.  I cut, pieced, trimmed carefully and pressed and my block came out to a almost perfect six inches!  Which would make it five and a half inches finished.  How do you take a 12.5" block, divide in half and increase some sizes and come up short?  A complete mystery to me.

Today, I tried again...after more googling to find my instructions, a little header came up at the bottom of the page....6 inch snail trail!  It was NOT there yesterday!  After more cutting, piecing, pressing and trimming, I now have a Snail Trail block that required very little trimming to be 6.5". Just three more to go now.  After comparing the two blocks, I found that there is an extra round of triangles that wasn't in the first pattern.  Here are the two blocks together.

Here's the link to the pattern if anyone else is still looking.
6" Snail Trail block

UPDATE...Here is the corrected version of the Snail Trail block.  Even though I cut all my pieces and laid them out in order, I seem to have rotated the center as I was adding another round which gives the little false trail effect in the block above.

Just a hint...it's probably easier to just call any error a potholder and start over! I think it took me longer to take the center out and resew than it would have to recut and sew from scratch!