I think I know but will wait and give others a chance to reply.
He had trouble expressing perception normally on canvas.... which may or may not have had something to do with later behaviour.
Regards,
Doc Sharptail
wasn't this the guy with the funny mustache?
He didn't have a funny 'stash until his big 'stash messed up his WW1 gas mask seal and he got a good whiff of phosgene. SW
Oh, I know, I know.
If I should die before I wake...great,a little more sleep.
You may notice the complete lack of people in his paintings.
As an artist he'd have made a terrible house painter!