I made this blanket in the summer last year fro Osiris. It was a labour of love I can tell you! I got the pattern from Sprite Stitch from someone who used it for a cross stitch pattern. I broke it up into squares of 20 x 20 pixels and crocheted each square using a 5mm hook and a Tunisian stitch. It took me a little while to work how to change colours and really I should have invested in a Tunisian crochet hook.
Things I have learnt from making this blanket:
Buy a long hook
Maybe do long strips instead of squares
That people are impressed easily because I can really see all the flaws in this but people have been very nice.