It was plagued with issues; one of the sleeve is wrong side out and I only realized it when everything was almost done (luckily the pattern is symmetric and it is barely noticeable) and the swirl moved while I was sewing it on (and the sewing machine got stuck multiple times: next time I'm using interfacing, full stop.), and it's a bit deformed, but it's done.
For the swirl, I used Inkscape to Simplify (Ctrl-L) the original Debian Swirl a few times, removed the isolated bits, adjusted some spline nodes by hand and printed on paper. I've then cut, used water soluble glue to attach it to the wrong side of a scrap of red fabric, cut the fabric, removed the paper and then pinned and sewed the fabric on the pajama top. As mentioned above, the next time I'm doing something like this, some interfacing will be involved somewhere, to keep me sane and the sewing machine happy.
Blogging, because it is somewhat relevant to Free Software :) and there are even sources, under a DFSG-Free license :)