A greeble, or nurnie, is a small piece of detailing added to break up the surface of an object to add visual interest to a surface or object, particularly in movie special effects. They serve no real purpose other than to add complexity to the object, and cause the flow of the eye over the surface of the object to be interrupted, usually giving the impression of increased size.
A greeble is essentially the small detailed technical part of a larger object. The detail can be made from geometric primitives, including cylinders, cubes, and rectangles, combined to create intricate, but meaningless, surface detail. Greebles are commonly found on models or drawings of fictional spacecraft in science fiction.
From Wikipedia, via Metafilter.
There’s a character on a show I work on who wears a shiny silver helmet with some greebles on it. The greebles are made of little pieces of spaceship toys, broken apart and glued to the helmet in mostly-symmetrical patterns. Some are recognizable pieces of Happy Meal toys. I remember seeing a behind-the scenes Star Trek footage that showed how pieces of disposable razors made the pontoons on a shuttlecraft model.
By the way, haven’t razors come a long way? Goodness, technology. That razor pic is from here. But that’s not my point. My point is that this Hallowe’en you need to make sure you put Greebles on your techie-looking costume, and take your robot suit from crappy to snappy.