I thought it would be fun to try one of the half blocks, so I selected one of the easy ones. I think it's really quite cute.
Somewhere I read that there are two options with the half and quarter blocks - one is to simply make up the block and chop it in half, and the other option is to add the appropriate seam allowances. I elected to add the seam allowances - it was just my feeling that it would make the final construction less than perfect if I had to stretch any of the blocks to compensate for the seam allowances being absent. If you've had a different experience, be sure to let me know, because it would be easier to just chop them in half. For me, I think I'm taking the lengthier option.