“One thing I wanted to do with Prolog, pick some sort of better things. Better stuff should happen when it fails. The other problem with prolog is that you could only do one thing, and you can only have one process. So I wanted and I thought Prolog was really great. I made an algebra to describe telephony in Prolog but the only trouble was you could only describe one process and if they didn't do what you'd expected them to do when you got failure, it didn't work.”