OK. I’m not one to let go of a problem. I obviously know who had done what or not because Sceptical told me. I needed to know why it worked. So I got my resident geniuses on the case and got an explanation I could take in. And it goes like this:
The sighted prisoners could each see either two green hats or one red and one green hat. If the blind prisoner was wearing a red hat then one of the others would either have seen two red hats or noticed that the second sighted person had not seen two reds and spoken up.
I thought I’d put this up on the basis that if I needed it explained like this, then someone else probably needs it too.
I’m sure I’d have got it if my sinuses hadn’t been playing up.