So I don't know if you know about this or not, in fact I don't know if it's been posted (then this is a refresh). The dream clock was 'invented' by a member of LD4ALL he was considered a god over there because of his pure skill. He uses the dream clock as a time distortion method to prolong lucid dreams. Now here is the key thing he knows that he is not spending hours in the dreamworld, that is just his perception of it. Don't think that this is like inception, in fact forget about that all together for this, there is no relation. So he has been in lucid dreams which can fell like a whole day!! So how it works is while he is in a dream (normally going to a void first) he will manifest a holographic clock which had two sides. One with real time on (something like that) and the other one with dream time on. He can then change the times to let's say 1 hour real time and 4 hours dream time. He even writes out most of them, not the really long ones though. I have stopped going on LD4all, I was really just a lurker, but I thought I would 'revive' this here. I can help with any questions

(Oh and if your an master LDer I would really like you to try this out, I only used it once but the results were amazing)