i used dk weight acrylic yarn and a 3mm hook and he is 13" high to the top of his thingy. you can use any gauge yarn you like, but make sure you size down a couple of hook sizes to keep the fabric tight and stop the stuffing from showing/escaping.
his hands and feet, as well as the bottom third of his body are stuffed with poly pellets - i got mine from ebay. you stuff the hands and feet as you're making them and stitch across the opening with the tail of your yarn to stop them all escaping upwards. using pellets in the bottom part of the body helps him to sit up, you then stuff the rest of the body and the head with regular fluffy stuffing. i've machine washed amigurumi stuffed this way and be warned the body stuffing will all mix up if you do this - if i wanted to make sure of machine washability i'd work a circle to sew inside the body and keep the stuffings separate.
there are various changes i would make if i were doing him over - i'd taper his body out more gently so he ended up slightly slimmer, and make his arms a bit shorter. i'd also consider working the arms and legs in rows (turning at the end of each) rather than in spirals so the stripes join up. i'd also use a darker grey for his arms and legs (the hands and feet and the connector thingies on his arms should stay in the lighter grey). i'd also stuff him more, really cram it in :)
this pattern assumes you've done amigurumi before and can work from row charts, you just need to do a little maths to work out how often to work the increases/decreases. each round is started with a magic loop and worked in a spiral. use a stitch marker to keep the first/last stitch, you can keep a written tally of the number of rows, or i use a kids abacus.
disclaimer: i haven't tested this, i wrote it down as i did it and may well have missed the odd bit out - if you find anything please let me know. this won't make the new improved bender described above, but one the same shape as mine.
i'm happy to share this pattern but please credit me and don't use it to make stuff to sell.
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