Haha, its horrible stuff, isn't it? I think the accepted wisdom is that it's virtually impossible to do. In fact, I think Polycell now sell a product especially for covering up Artex, presumably making your ceiling half an inch lower in the process.Quite. I remember a miserable weekend in Dorset scraping off Artex in my friend's bathroom.
This place is all Artexed ceilings, but they're quite high so you don't really notice them.

You'll have real problems getting the tesselation working - especially forming another horizontal line at the top. The colours are all blotchy and the edges are rough.

