My first introduction to FORTH was GraFORTH on the Apple ][ (which has all but disappeared from the internets). It was memorable because it was fast as blazes,

My first introduction to FORTH was GraFORTH on the Apple ][ (which has all but disappeared from the internets). It was memorable because it was fast as blazes, essentially compiling routines to a sequence of JSRs, and it featured built-in wireframe 3D graphics primitives. This was exciting at a time where naively clearing the screen with line() routines took several seconds.