I've picked a basic straight stitch for this exercise and have used a variety of different threads and yarns, including embroidery floss, wool, viscose and hand-dyed stranded embroidery cotton, all in shades of greens.
I have also dusted off the trusty Bernina (a 1090 for any Bernina
buffs out there) and started working my way through all the different
stitches and stitch combinations. I also (deep breath) read the
instruction manual. This alone has been a revelation! Although I've used
it quite a bit it only really sees the light of day for the usual
household jobs like hemming, patching and (very occasionally) a bit of
home-sewing - cushions and the like. (Good job I know the DH doesn't
read my blog given how much it cost - oops).
I'm amazed
by how much it can do that I never realized so this is going to be a
great exercise. So far I'm up to stitch 4 of 28. It isn't a swanky
computerised affair but has 14 decorative stitches as well as all the
normal ones so I've lots still to play with. And the normal stitches are
proving interesting in themselves. I'm planning to build my swatches
into a nice reference collection so they'll be useful after the course
too.