World Cup Soccer 2010 Green Point Stadium wrapped in mesh liner sheets

Well I must say it gets more interesting by the day ...now there are 2 white sheets hanging in the front as well as 5 long strips of the PTFE mesh membrane on the left

I drove to the Hamiltons Rugby club to have a closer look but it started raining, so no shots from there...well the first 3 strips they put up already look tatty and dirty, the 2 newer strips look lighter and cleaner, then the 2 half sheets in the front .. they remind me of bed sheets, I dont understand why they are so much lighter then the rest ?