wozItDo: Tiny IQ puzzel, BIG challenge

I think of this puzzle as the electronic equivalent of those annoying “IQ” puzzles (e.g. where you have to get two parts apart). A wozItDo has just one button and three LEDs and all you have to do is to work out what it does. Beware: it’s deceptively tricky and once you think you’ve cracked it, there’s still more.
So what’s with the name? We’ll about 30 years ago I made my first “computer”. A 6502 MPU with a keypad, some 7-segment LEDs and a handful of other bits. I was inordinately proud of it but when I showed it off to other people they seemed unimpressed and often asked “But what’s it do?” Nothing, really, but that’s not the point.
When I started playing with the ATTINY85 I was super impressed. It’s this understated little 8 pin DIL that costs <$2 but burred inside is the enormous complexity of a full blown ATMEL MCU. And all you need to give it is power. wozItDo is in that spirit. It looks disarmingly simple but there a lot more than first meets the eye. To give you an idea there’s about 1200 lines of source code packed away inside that tiny 8 pin chip.
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