Oh, you're right, I'd forgotten about the dogging episode. So we're they actually making Morse code letters or was John just trying to make letters out of random flashes, I wonder? I was confused because I interpreted the flashing of the lights in Henry's house as some sort of response, like Barrymore responding in the original story, but now that I think about it, it was probably just Henry hallucinating or some sort of motion sensing light going on and off, or maybe something Franklyn set up to freak him out.

Yeah, I liked the concept too, I always like stepping inside Sherlock's brain and I sort of like the idea that the place he's set up for himself is not some sort of mental building, but more of a computer hard drive. I think it would have looked better without the fast-mo.