> Pedantic note to people using 'ASCII' in this thread (although Monosketch tool does't claim to be ASCII).
In big ASCII letters on the landing page: Unleash your ideas with ASCII [] MonoSketch is a powerful ASCII sketching and diagramming app that lets you effortlessly transform your ideas into visually stunning designs.
A historical note: even though the line/box-drawing characters go back to the IBM PC, they aren't ASCII. The PC used Code page 437, which added a bunch of characters to ASCII. To be genuinely ASCII, you need to draw your boxes with pipes and hyphens (| and -).