Help needed - Fabrication

Hi all, i'm a newbie to GH, trying to learn by doing Khabazi's step-by-step instructions (the ebook 'Algorithmic modelling'). I got stuck at this particular bit from page 155 to page 168 regarding Fabrication (got the sections alright but they don't orient flat on the page and it went downhill from there). I can't see where I got it wrong. Anyone done this or have the ghx file? I need it for comparison :(
Thank you.