This was like creating optical illusions, as the grey changed its tone dependent on the background colour and also it could be seen to change the background sometimes. Grey seems to be swalled by the background to become a reflection of the mixed primary colours (when on a secondary etc) and when on a primary colour it is almost a hole, adding depth towards nothingness. Mmm
A note added in retrospect to this activity, when I was mixing colours to match an image Stage 3 exercise 3, I got very confused with the grey. My first views were that there was a lot of grey, but as I worked further, I realised it was not grey I was seeing but the effect of the other colours on each other. A cautionary tale.