The IBM 2741, a slow but letter-quality printing device and terminal based on the IBM Selectric typewriter. The golf ball was a little spherical frob bearing reversed embossed images of 88 different characters arranged on four parallels of latitude; one could change the font by swapping in a different golf ball. The print element spun and jerked alarmingly in action and when in motion was sometimes described as an infuriated golf ball. This was the technology that enabled APL to use a non-EBCDIC, non-ASCII, and in fact completely non-standard character set. This put it 10 years ahead of its time — where it stayed, firmly rooted, for the next 20, until character displays gave way to programmable bit-mapped devices with the flexibility to support other character sets.