Many thanks. As you probably guessed I have no prior experience with VTK, so I’m most likely doing some dumb things. I’ve updated my JSFiddle.
https://jsfiddle.net/k_udilovich/r3joqg74/89/
No errors now, but the color-coded visual as I expected with colors driven by nodal scalars still doesn’t show up. Sorry about being such a pest 
