<p>But a thing I was particularly pleased with, and with hindsight I still am: my mother found it easy to use. This was a surprise because I hadn&#39;t deliberately made it that way! Usability by people other than me wasn&#39;t much on my radar yet, at that age.</p><p>But, by luck, I made a good UI choice, which was to write all the menus so that they could be read as English sentences. So a user wouldn&#39;t need to learn any of the various complicated &#39;visual grammars&#39; that sophisticated UIs use to signal the available keystrokes, mouse actions etc. They&#39;d only need to read an English sentence telling you what options you have and what key to press to do each one, then pick one of them, and press that key.</p><p>The online help screens had the same feature: instead of containing obscure notations like ^B, they said &quot;Press Ctrl with: B for bold, ...&quot;, and at the bottom, the all-important prompt for what to do next: &quot;Now press any key to exit Help&quot;.</p><p>3/3</p>