I was going to do that but did not yet. I must say that I generally try to do not do any 'frontend' stuff. So sure I do prototypes of the frontends but someone else does a UX/UI and the coding of that. So my thinking is architectural, the different components, algorithms and low level implementations. All of these I can work out in my head with some Google + paper which means I can walk during that. If I would have to do HTML/CSS it would not work; I am not sure if that's because i'm just not that fast with it, but it's way too much iteration to not make me sit in front of a (large) screen for too long. For instance, when I have to do embedded work, thinking up the coding, let's say for a RISC chip, can be worked out to quite a lot of detail before typing 1 line. Worse; if I don't work it out in detail, I'll just end up frustrated behind a debugger and a lot of crashes. I have done that since I was young as assembly or low level C never worked well for me while iterating; only in recent years I realised that this applies to other projects as well.

Another thing that has to be said is that peripheral vision is important; when I walk writing or staring in my phone, I don't have issues tripping, walking into things etc. I would be very handicapped if I did not have that. And another thing with my eyes is that I read very very small print which is why I can work quite comfortably on small tablets / computers (I am looking forward to receiving the Pyra).