Now, how about reducing the resolution and increasing the speed? E.g. a one pixel display and a one pixel camera that runs at MHz or GHz Speed? You'll have to a

Now, how about reducing the resolution and increasing the speed? E.g. a one pixel display and a one pixel camera that runs at MHz or GHz Speed? You'll have to add some modulation though, otherwise you can't sync the two devices. Wait, isn't that called FSO or LiFi :D?