Garden Pumptrack

We have two gardens backing onto our house. Our dad is letting us use the smaller one for whatever we wanted so we thought about it for a bit and decided to build a very small pump track because we both have some experience in this area.This is an image of the pump track my brother had built with me, our dad and several other helpers:
Before day 1 work:
Unsecure image, only https images allowed: http://photos-e.ak.fbcdn.net/hphotos-ak-snc3/hs008.snc3/11558_190306580944_680050944_3047957_1564870_n.jpgAfter day 1 work:
Got a bit bored this afternoon and after my brother had drawn some rough sketches on a piece of paper, I took his ideas further and drew them up on Google SketchUp:
From the backdoor:
Side overview:
Rear Overview:
More pics and words to follow once more work has been done