'I do remember my very supportive mother testing it for me along the way. I was only a Basic programmer so puzzle/thought games were a natural fit as well.' Mined-Out, which - perhaps unwittingly - laid the foundation for Minesweeper. So a block/grid game was a natural for this computer.

'You could only have 2 different colours in each 'character square' which was 8 by 8 pixels big. 'Mined-Out was developed partly due to the Sinclair Spectrum's limitations of colour blocks on the screen,' Andrew recounts. Soon he moved on to the ZX81, and his very first commercial game, Mined-Out. Andrew has had a long career in games which began when, as a child, he'd modify his wooden pinball table with nails and elastic bands. That credit goes to a lesser known, tightly designed game by Ian Andrew. Minesweeper wasn't the first of its kind. The mechanical logic would make a chess grandmaster grin, while bold gamblers still chase quicker and quicker clearance times. There's the smiley face when you do well, the gasp of failure and the cross-eyed look of death when you fare slightly worse. The levels vary from 8x8 grids up to huge 64圆4 grids. Everyone can recount the basics the left-mouse button reveals the contents of a tile whilst the right flags a tile as containing a mine.

It's video game wallpaper that's silently seeped into countless people's lives.

Minesweeper was the original roguelike