I have experienced this many times.
I did a Polyphasic Sleep experiment. I sleep only 1.5 hours in a 24 hour period. I slept 6 times around the clock. Every four hours I would take a 15 min nap. I did this for 273 days straight. Now I am only sleeping 45 minutes in every 24 hour period (I call it Powiull sleep, because nobody else has ever been documented sleeping this little for this long) and I still am experiencing the same positive effects:
1. In the first 48 hour, my intuition heightened, the mental chatter cleared (like that of a mediation state), and I begin to realize how to live in the moment rather than by a day and night schedule. I begin at once writing what I was receiving from within.
2. My logical mind dulled while my creative imaginative mind accelerated giving me a child-like sense of everything being exciting, new, fun and perfectly fine. Unlocking this part of my mind again allowed me to understand the power of the imagination to solve any problem from within (the key of life) using the engine to creative power and see many more choices that my logic couldn’t imagine by putting limiting beliefs on Self.
3. Time became non-realistic in all terms that time can be perceived since I am up for 23 hours and 15 minutes in a 24 hour period. I came to understand time as non-existent because there is so much of it. When people refer to yesterday, I can not place when one moment to a next moment was yesterday. It is all a continuous streaming reality with no approach or separation between days and nights to me. I notice the shift from day to night but I do not shift with it in form of a schedule. Instead I listen to my physical, emotional and mental bodies in the moment to signal me when it is time to do something, you would be surprised by how much you do things based on habit of a night/ day cycle.
4. During the process of adopting this sleeping pattern all my five senses dulled and when all the five senses returned, they were much sharper, aware, alert, alive and clear. As if I were in a dream all my life and just waking up to a new world that is much more vibrate and vivid.
5. I felt the elevation of my consciousness to higher states of awareness. I also feel a connection to myself, to everyone else and everything around me. This connection has made my conversations with people much more meaningful and helpful in developing and growing conscious states.
6. My dreams are more vivid, intense, and real. I often have lucid dreams and I remember my dreams quite easily, which is very helpful in consciousness advancement since dreams are a reflection of reality.
7. The ability to remember things (on a short-term and long-term span) has increased dramatically, the motivation I have has improved, and my concentration as well. I literally feel like a much more intelligent person, as if my brain waves are more active. Rather that is the case or not, it is very self-reassuring and builds confidence to a higher focus.
8. After every nap I feel refreshed, energized, wide-awake, with no feelings of tiredness, drowsiness or grogginess. Even when my naps times come around I still do not feel tired, drowsy or groggy. These feelings are non-existent to me ever since I adopted this sleeping pattern. When a naptime is close (15-20 minutes) my body gives me a signal by making my eyes slightly heavier and relaxing my body a bit more. Nothing too intense, just enough to let me know that naptime is close and every nap feels like an eight hour restful sleep.
9. All activities of stress, worry, depression, negative thoughts and seeing things as problems have vanished. The mind is the corporate that leads to all these things. The mental noise in the background that is in continuous struggle trying to make things better and always questioning with “what if” dilemmas. This sleeping pattern puts that mind chatter to rest and opens up a new way of thinking.
10. Jet lag is the result of the circadian rhythm being unbalanced. Circadian rhythm is a natural rhythm that the body adopts based on day and night schedules. When you adopt the polyphasic sleeping pattern then the circadian rhythm is replaced since you will no longer have a day and night schedule, making the experience of jet lag nonexistent.
Including clearer thoughts, feeling more awake, adjusted, aware, alive, vibrant, and energized. Also a growth in intuition, a unique scenery perception, happier with life on every level, no negative thoughts or feelings of depression, more aware to the world around me, answers to any questions I was seeking, more insight, seeing more inner knowledge, experiencing more wisdom, feeling more peaceful, and more of everything that I define myself to be.
If that is not flow, then I am not sure what is 
and the good news is I didn’t have to practice 10,000 hours, I just had to stay mentally focused to get through the adoption period.