[callumprentice]

Some of the things I considered:

* Connecting wirelessly to the computer would be ideal. Camo and Apple's own Continuity Camera do this so it's certainly possible

* There should be a computer companion app that lets you tweak the position of the monitor segment displayed on the phone screen - both for position, offset, color, temperature etc.

* There would be a parallax effect, even with how thin today's phones are - I wonder if you could correct for that in the phone app and make it appear to be on the same plane.

* Should it hand upside down from the top of the computer/laptop screen via a (magnetic?) widget or allow for positioning with a tall, skinny phone stand on the desktop in front of the monitor? Ideally both I guess.. Even left/right side if that made the engineering easier.