Use quotation marks “” to enclose your text and escape special characters, e.g. in your example: graph TD question1{“Gas tank less than 1/8?”} action1[“Fill tank to 100%”] question1– Yes –>action1 will produce this diagram: This is now documented in the official documentation.
I’m reasonably certain that it predates disk drives, and goes back to a considerably older technology: drum memory: Another possibility (or maybe the choice was based on both) is a still older technology: mercury tank memory: You may have seen the symbol oriented horizontally instead of vertically, but horizontal drums were common as well:
There is an Online Railroad Diagram Generator. It creates SVG syntax diagrams, also known as railroad diagrams, from context-free grammars specified in EBNF. You can copy the SVG code or take screen shots. You have to type in the grammar and it’ll make the diagram. For example, to create the first railroad diagram you show, … Read more