I really can concentrate when I don't have any distractions - I used to listen to music on head/earphones, - walkman, then CD player & finally mp3 player, when I was at work in front of my CAD screen. I could be ignorant of things going on just out of my sight line. I had a phone with a blinking light that told me when I had a call.................
I'd sit and concentrate, every hour, I would get up, go and look out of the window ( to exercise my eyes ). Comfort breaks & coffee refuelling ( free ) as necessary! At first the boss didn't like it, but he realised after a while that this was the way I worked best - the same with my seemingly random visits to the production line ( working things out in my mind )
Looking back I now realise that the stress I was under, due to tight deadlines, long hours, poor eating/drinking habits was the cause of my diabetes ( no family history of it ). One of the project managers described my work regime as 'flogging a willing horse'
Easy to see now, but the amount of design work done was quite remarkable!
Dave