I was reading this a few hours in the Guardian, but was rushing and couldn't find the link
I've done the test and a bit shocked about my result - "Your boundary is at hue 188, bluer than 98% of the population. For you, turquoise is green"
Really, why am I surprised, I have Aphantasia, completely unrelated. Aphantasia is the inability to visualise in your 'mind's eye' when you close your eyes.
Long story short, if I close my eyes and try to visualise my children, or anything at all, I just see blackness.
Brief and entertaining article about Aphantasia here: https://www.facebook.com/notes/2862324277332876/