The Mountain hat : a free knitting pattern

I wanted to make a present for a male friend's birthday, who likes to go trekking.
I decided to design my own hat, and also wanted to have a go at designing in excel:

So this was the final result.

Materials:
stylecraft special aran in Denim, Graphite and White, which I purchased from LoveKnitting.com 
(I thoroughly recommend this website, the service is amazing!) I bought one ball of each colour and had loads left over.
4.5 mm circular needles.

Pattern
I haven't included any instructions for shaping, but it's just decrease as necessary on each side of the panel.
An adult hat requires 4 panels, so start with casting on 96 stitches, knit in the round following pattern. the p represents purl stitches.
If it doesn't make sense, this is the basic pattern that the hat is based on, which should explain everything.