There are also computed sprites (computing the sprite image by code based on input), which is what Spacewar! actually used. The spaceship graphics where defined

There are also computed sprites (computing the sprite image by code based on input), which is what Spacewar! actually used. The spaceship graphics where defined as drawing commands (octal digits encoding directions like down, down and left, down and right, left, right, etc, one step each) in octal strings. Dan Edwards provided an ingenious "outline compiler", which compiled JIT machine code from these commands to draw the spaceships at the given rotational angle. Here, the article is actually in error: Spacewar! did use sprites. The spaceship outlines could be easily defined by pattern strings, but were also drawn as fast as possible by their own mechanism, using x/y coordinates and an angle as the input. However, this was done purely in software and there was no special hardware facility for this. Edit: Hardware sprites (as in Computer Space) were historically a cost effective replacement to something to the same effect without the need of a CPU. Later, with the advent of dedicated graphics chips, it became also a means of managing and accelerating graphics. A key feature of these chips was that these do also collision detection when mixing the image.