Remember this beauty? I'm playing it now on my old Amiga 1200.

My question is: How do you think they represented the terrain, data structure wise? Obviously it's some kind of points, with a height. Or hexagons. And how did they decide which dots were buildable?

EDIT: I could rephrase the question to say "how do I achieve this kind of terrain", but I would still only be interested in how to do it on a machine with 1 MB of RAM and a 7 Mhz processor, because this is the machine i currently developing games for. If that seems like a vague or meaningless question to you, that's alright, but I'm still curious if someone has any knowledge about this.