Okay, in our last little vignette into the history of agent-bnased modelling, we're going to talk about particle systems and computer graphics. So, early on in computer graphics, visualisations were essentially accompalished by creating large, flat surfaces and then combining in ways to create what was computer grpahics. And to tis day, a lot of computer grpahics is still done that way. Like you place textures on these polygons and you place them But there's another way to do graphics, which is to think of graphics, not as a polygon but just as a point, and you give that point a size. But your'e essentially mani;ulating the centre of that point rather than manipulating all four corners of a square.... and in fact, surfaces don't work very well for smoke, stars light or even birds, for that matter. So, instead you need some soft of point representation as we talked about. And this point representation of graphics came to be known as particle systems. And what's interesting is that once that you think of these things as points, well a lot of our physics models are actually written as points, as idealised points so then you can apply those physics models to computer graphics in a very easy and intuitive way and you can create interesting displays. in computer graphics. So, how does this relate to ABM? Well, particle systems also exhibit emergent phenomenon. So, for example, if I'm representing a bunch of red particles as a fire, then when they overlap, depending on how I've done the transparecies, they appear denser of lighter so I can get this like flickering flame like effect htat looks very similar to a fire, right.