mdmackillop, Thanks very much for your help to. I've gone with p45cal's solution as I understand how it works should it need tweaking in the future.

Quick question though regarding the code if you don't mind answering. I'm a bit confused by the sections below ralating to z, how does that work to determine the colour, or have i completely misunderstood it.

x = arr(i): y = arr(i + 1): z = arr(i + 2) .Color = z