Some mouse drivers used an upper ascii range (less used) and rendered 4 “arrow” cursor parts into it over 4 chars over which the cursor ought to be. And then re

Some mouse drivers used an upper ascii range (less used) and rendered 4 “arrow” cursor parts into it over 4 chars over which the cursor ought to be. And then replaced those 4 chars on screen temporarily. As a result you had a fully pixel-perfect cursor in text mode.