I have recently discovered on the internets that it is possible to have a Mac pretend it has a second/third/etc monitor, and to have another computer VNC to that monitor and thus the Mac gets to have 2 or more monitors without having 1 or more display connected directly to it.

I cannot find any open-source software out there that does what I want (so far, maybe I haven't searched hard enough), so I have decided to go and do it the hard way and try to create a solution all by myself. It kinda helps I'm doing a computer course at uni (or maybe the help would go the other way round) but I know that so far I am nowhere near the level required. So I would like to know what I should be learning to get to the level required.

One of the reasons I have for this is being able to watch movies on a decent sized conglomerate of screens from a decent distance... and being able to show off. And perhaps bragging rights that I did it all myself. And also get a second display when my Girlfriend isn't using her Mac.

Is it possible without breaking any licenses from Apple, and what would I need to learn, for me to code such a thing?

Many thanks in advance, and I hope I made sense

That's actually really rather cool

Oh, sorry, yeah. I know that's cool, but I was hoping to learn how to do such things myself. That's actually the thing that made me think "well if he can code it so can I". Admittedly I would probably make enough money from finding 5 cent coins on the ground in the time it would take me to learn to code something to do that, to be able to pay for the software... but I wouldn't know how to code it if I just focused on finding 5 cent coins on the ground.