My neck is asymmetrical because some years back I used to often lie in bed while using a laptop, and would prop my head up on my left elbow, but not my right because there was a wall in the way. In general, using a laptop while lying in bed is an ergonomics nightmare. The ideal would be to lie on your back with the laptop suspended in the air above you, except that that would make typing inconvenient.

So a friend recently blew my mind by informing me that prism glasses are a thing. These rotate your field of vision 90 degrees downwards, so that you can lie on your back and look straight up while still seeing your laptop. I have tried these and highly recommend them.

That said: You should probably not do non-sleep/sex things in bed because that can contribute to insomnia. I recommend trying a standing desk, by putting a box or a chair on top of your desk and putting your laptop on top of that, then just standing permanently; it will be painful at first. Also currently experimenting with only allowing myself to sit down with my laptop if I'm at the same time doing the highest-value thing I could be doing (which is usually ugh-fielded and unpleasant because otherwise I'd have already done it).

Another thing: I have a crankish theory that looking downwards lowers your unconscious estimation of your own social status (which seems to be partly what is meant by "confidence"/"self-esteem"). If that's true, prism glasses and standing desks could increase confidence.

I am seeking a mathematical construct to use as a logical coin for the purpose of making hypothetical decision theory problems slightly more aesthetically pleasing. The required features are:

NP-complete problems have many of the desired features but I don't know off the top of my head any that can be used as indexable fair coin.

Can anyone suggest some candidates?

My first idea is to use something based on cryptography. For example, using the parity of the pre-image of a particular output from a hash function.

That is, the parity of x in this equation:

f(x) = n, where n is your index variable and f is some hash function assumed to be hard to invert.

This does require assuming that the hash function is actually hard, but that both seems reasonable and is at least something that actual humans can't provide a counter example for. It's also relatively very fast to go from x to n, so this scheme is easy to verify.