Celtic (Ish) Cables

Cables in crochet that almost look like a Celtic Knot!
I've always wanted to do cables, but I loathe (read: fairly suck at) knitting, so when recently I discovered that by using front and back post stitches in crochet you could achieve a similar effect I got REALLY excited. The excitement waned a littled when I went internet searching and couldn't find any interesting patterns for it. All I could find was straight and twist, which didn't hold my interest very long. I wanted to do the pretty celtic knot stuff that the knitters do. So I sat down with some graph paper and a pencil and a bunch of pictures of celtic knots and I worked out how to do it.

This one didn't work out exactly as planned, some of the cross overs go the wrong way, (which is why the "ish" is in the title. It's not quite a celtic knot). But in any case, the pattern below creates what is shown in the picture. And the pattern has been tested by my mother (she needed a fair amount of coaxing because she'd never done front post and back post before but we got there in the end) and changes and notes added to clarify things. It's pretty important that you read the notes before starting out. I'm sorry if it's a little confusing. (Some vital notes are in the downloadable document)