To answer the question I asked myself before starting the experiment "Is 20 minutes of sleep every four hours enough for a scientist?", the answer is NO!
Twenty minutes of sleep every 4 hours is not enough for a scientist!
Main reason is that going to sleep every four hours interrupts the work I was doing and after 20 minute sleep I have to put the ideas back together again. Also I found hard to concentrate right after I wake up from the nap. So it took more like 30-40 minutes to get back on track where I left off.
The method of sleeping 3 hours a day is better and I am overall satisfied with it.
Today I have slept just 1 hour (in two 30 minute naps) and it's 12pm. I am soon going to have one 1.5 hour nap and then maybe another 30 minute nap.