Thanks Tim, perhaps I wasn’t making my point well. His query went something like this “the track line is yellow, which makes sense, but some elements of the ‘curtain’ are yellow, and some blue. At first glance it would appear that one side of the ‘curtain’ is yellow and the reverse is blue. But when you look at the graphic, that’s not correct.

If there’s no explanation, never mind. We’ll move on!