For the pattern I’m working on (Ellerbe Mitts), I came up with an interesting decrease that turns out to have been invented more than once already (not really a surprise to me).
The name other people use for this one is Bunny Ears Back (because it’s a variant of another decrease called Bunny Ears).
Anyway, I’ve worked up a handout (also available as a PDF) to go with the pattern. Here’s the text of it, with illustrations.
Bunny Ears Back
a centered single decrease
Say you’re making mirrored decreases in an upside down V over an odd number of stitches. When you get to the top, you have three stitches left that need to become two. The easy thing to do is to make one decrease and knit the other stitch. However, this isn’t symmetrical and can irritate those of us who like parallel construction. I was recently in this situation and came up with an alternative; I was sure I was not the first to think of this, and indeed, I found a blog post by another inventor of this decrease.
The quick description of this is that you first start by making a left-leaning decrease with the first two stitches, then pick up the second of the stitches again and make a right leaning decrease. Here are some diagrams:
Make a left-leaning decrease in whatever way you prefer. Result:
Pick up the second stitch with the left needle:
Knit the two stitches on the left needle together so they lean to the right. (Combination knitters might need to reseat the third stitch so the right leg is in front.)
The middle stitch appears to have disappeared!
The regular bunny ears decrease works on the same principle, except that the first decrease is k2tog and the second decrease is ssk. The middle stitch ends up sitting in front, wrapped around both resulting stitches.
Please let me know if you have questions.