The following is a step-by-step description of how I wrote the program, and why I wrote it as I did. The program as described applies to the TS 2068. Some of the principles described can be modified to work on the good olโ ZX81/TS 1000, but only with serious limitations. The biggest problem with the ZX81 is the limited character font, including the absence of lower-case letters. And the membrane keyboard sort of discourages one from thinking in terms of word-processing, unless a keyboard enhancer has been added.