I've been reading about the advancements in Superstring Theory, now M-Theory, and it's theoretical cosmological ramifications. String Theory, which resolves all mathematical conflicts between the macro, cosmological realm of General Relativity and the micro, subatomic world of Quantum Mechanics — if correct — predicts 7 extra spacial dimensions that exist in every point of space right next to us that we cannot see or even detect experimentally. Our entire detectable universe exits in 3 dimensions (Up-Down, Left-Right, Back-Forth) plus one dimension of time. Recent discoveries in String Theory/M-Theory have shown that along with single vibrating strings of energy that there may also be vibrating, multiple-dimensional "branes" and some physicists believe we may be living within a supernormous 3-Brane that is our Universe. Another cosmological origin theory has another flat 3-brane universe running along side of ours connected by sticky, segment-like extra-dimensional strings whose plates bang together every eternity or so creating a cycle of Big Bangs.
Well, before I read about that I concocted the attached diagram of what the other hidden dimensions might be. My idea is quite simple and it involves the existence of a "dream state." Descartes once said that you could never convince him that he was either awake or dreaming because anything that existed in his perceived reality could also occur while he was dreaming. So I matched the 3 dimensions of space and one dimension of time that we experience with the 3 dimensions of space and one dimension of time we can experience while dreaming which makes 8 dimensions then added an extra dimension for the dream state itself plus another time dimension for the Dream State (time is really fucked with when dreaming) to make 10 dimensions. I made sure the Dream State/ Time 3 dimension intersected both the real world and the dream world and drew a small sphere in the center, intersecting everything — ironically making an "X" — to account for the missing 11th dimension. This is, of course, a festive-inspired guess.