The peak pose of the class I yesterday was lotus, which I've attempted before and failed, so naturally I was expecting to have to sit it out. However when the pose came around towards the end of the class we where lead through a few lead in poses including half lotus. Much to my surprise (and my teachers) I managed to get into lotus pose on both sites without much difficulty. This was sitting on a block, I tried it again in my practice today and I can do without, though it's very strong.
I've been very surprised with how much progress I've been making, considering that I was contemplating eliminating downdog from my practice just a few months ago. I think this goes to show the importance of keeping on trying poses even if you can't do them today, things do improve over time, and with regular practice using good methodology, rapid progress is possible.