It will occupy one bay of the fence surrounding the playground. The CDs will be a couple inches away from the fence so they can move in the wind. I'm hoping it will make the whole fish shimmer.
I've done a little test section:
I've now installed the frame, pictured below:
It's a windy site so I decided to keep the CDs further away from the fence to try and avoid them being bashed and broken. I bolted 6x2s to the existing fence posts and then attached the top and bottom planks, also 6x2s, using coach screws. So the CDs will be 20cm/8 inches away from the fence.
I've drawn the design full scale onto some black garden weed suppressing membrane (it was cheap and I can re-use it in my garden), which is rolled around the top plank at present, so that it doesn't get torn to shreds by the wind.
I've also attached 34 lengths of fishing line to the top plank using staples. When I've unrolled and attached the black membrane I'll stretch the fishing line onto some corresponding staples on the bottom plank just before the children start installing the CDs.
The CDs will have to be installed from the top down. While the installation is in progress I'll hold the lines in place with bottle corks with a cut in their tops. When it's finished, I'll stretch the lines and tie them off.