The formula needs to account for the reality that with young children your "parental duties" expands to occupy all free time when kids are awake. And also shifts other chores into any free time slots when kids are asleep.
Kids are asleep. Time to clean the kitchen, do the dishes, switch the laundry, cut some veggies for tomorrow's dinner, and then find somewhere softer than last night to pass out.
I don't feel it's my duty to entertain my kinds every waking hour, so if they have to settle with watching me fold the laundry or unload the dishwasher, so be it.
This probably won't win me the father-of-the-year award, and it is parenting-style me and my girlfriend don't always agree about, but I refuse to sacrifice all my free time for my children.
I'm curious for a similar explanation for how decryption would work though; a trapdoor function is nice and all, but it's only half of the story if there is no 'way out'.
So I suppose I am saying: good question, I wonder about the same thing.
I hadn't even heard of the fact there currently was a world expo in Kazachstan if it wasn't for this article. For previous expo's I at least remember them having quite some coverage in the news.
One hypothesis, developed at Oxford University, is that the hexagon forms where there is a steep latitudinal gradient in the speed of the atmospheric winds in Saturn's atmosphere. Similar regular shapes were created in the laboratory when a circular tank of liquid was rotated at different speeds at its centre and periphery. The most common shape was six sided, but shapes from three to eight sided were also produced. The shapes form in an area of turbulent flow between the two different rotating fluid bodies with dissimilar speeds
Source: https://en.wikipedia.org/wiki/Saturn's_hexagon
Paper (paywalled): http://www.sciencedirect.com/science/article/pii/S0019103509...
Only after calling her name three times and considerably raising my voice I got her attention again.
The show that was on was... the cooking channel! So the bar for television completely absorbing a child's attention seems quite low :-)