Well, what you have on the wall there are just a bunch of wispy things. Clouds are bigger - 'bout this big - and much puffier, like someone took a bag of cotton balls and -

[he just stops, dimly aware that all he's doing is just making flaily, wild gestures. that's no way to make a point.]

...Just give me that brush. It'd be easier if I showed you. [he holds out his hand.]