I've found some sources that claim IBM had gotten a patent on making a line thicker using digital means. Does such a patent exist or is this a myth?
Here is one example of the claim from a Forbes article by attorney Gary L. Reback
The chief blue suit orchestrated the presentation of the seven patents IBM claimed were infringed, the most prominent of which was IBM's notorious "fat lines" patent: To turn a thin line on a computer screen into a broad line, you go up and down an equal distance from the ends of the thin line and then connect the four points. You probably learned this technique for turning a line into a rectangle in seventh-grade geometry, and, doubtless, you believe it was devised by Euclid or some such 3,000-year-old thinker. Not according to the examiners of the USPTO, who awarded IBM a patent on the process.
I've never been able to find an actual patent for this on Google.