I had a copy of Masquerade as a youngster, and went through a period of being fairly obsessed with it. I would say I grew out of my deeper love of Williams's style of painting, pretty much, in my 20s. Now I'd say too many of them strike me as too fussily photorealistic, too clean, too inert. It's not a style that has aged very well, I think: that whole 'Marillion album-cover' school of British art. That said, there are a few of his that strike me as both beautiful and powerful. This, for instance: a detail from Macaroon (2013), showing a fold-out element of the frame
That detail, as a complete composition, is (I think) even more lovely than the whole image; though that's pretty fine too.
‘Could a rule be given from without, poetry would cease to be poetry, and sink into a mechanical art. It would be μóρφωσις, not ποίησις. The rules of the IMAGINATION are themselves the very powers of growth and production. The words to which they are reducible, present only the outlines and external appearance of the fruit. A deceptive counterfeit of the superficial form and colours may be elaborated; but the marble peach feels cold and heavy, and children only put it to their mouths.’ [Coleridge, Biographia ch. 18]
‘ποίησις’ (poiēsis) means ‘a making, a creation, a production’ and is used of poetry in Aristotle and Plato. ‘μóρφωσις’ (morphōsis) in essence means the same thing: ‘a shaping, a bringing into shape.’ But Coleridge has in mind the New Testament use of the word as ‘semblance’ or ‘outward appearance’, which the KJV translates as ‘form’: ‘An instructor of the foolish, a teacher of babes, which hast the form [μóρφωσις] of knowledge and of the truth in the law’ [Romans 2:20]; ‘Having a form [μóρφωσις] of godliness, but denying the power thereof: from such turn away’ [2 Timothy 3:5]. I trust that's clear.
There is much more on Coleridge at my other, Coleridgean blog.