Continuing from where I left off yesterday, the next few photos show the process of levelling the remaining blocks:
After measuring the diameter, I found that it had changed in some spots, and I made a few minor adjustments, but I'm not going to quibble over a two inch roundness error on a fire pit. The leftover block became the first on the second course of blocks:
The very last thing I did today was add 18 more blocks:
You may notice that the second course overhangs the first by a noticeable margin - that's because I want to keep gaps in the bottom only to let air in, but the upper courses need to be closed. Tomorrow, the second course will be closed, and a third may be added - at least partially, to bring it up to the final intended height.