The Forest - a computer simulation of orienteering. This was written originally for the Tandy TRS-80, one of the very first personal computers available in Britain (from 1978). That version was published by Molimerx but made only 8 sales. I then modified it for the Sinclair ZX Spectrum and John Phipps (Phipps Associates) marketed it much more successfully, though it was not exactly a fortune-generator. The screen graphics were very crude but the map was drawn to proper O-map standards. To start with there was just this map:
Subsequently Chris Barrington-Brown made a version for the BBC Microcomputer, with my agreement. In the course of that we devised a more realistic terrain-generation algorithm and produced another map:
More recently (2014) I have been experimenting with a version of The Forest that runs in any browser and is written in JavaScript (HTML 5, using graphics canvas). It is unfinished but runs well, so please try it. I would be interested in feedback (gr at grelf dot net) and I may develop it further.