On this day in 1985, Super Mario Bros. went on sale in Japan for Nintendo's Famicom. Shigeru Miyamoto directed it, Koji Kondo wrote the tunes that are still rattling round the inside of several hundred million skulls, and a small team squeezed the lot onto a cartridge holding roughly forty kilobytes. Less than a single photograph from the phone in your pocket. The whole Mushroom Kingdom, in the space of a decent paragraph of memory.

Here's the clever bit, though, and it isn't the storage. Nobody hands you a manual. You arrive on the left of the screen facing right, because that is where the empty space is, so you walk right. A small brown fellow ambles towards you and teaches you what touching things costs. A block above your head produces a mushroom, which helpfully bounces off a pipe and comes back at you, so that the lesson lands whether you want it or not. By the time you reach the first pit you have been taught run, jump, hit, grow — and not a word of instruction anywhere.

I spent my working life on exchanges where the instruction card was longer than the equipment. A machine that explains itself by being played is a rare and generous thing, and forty-one years on, it still does.