The second painting, notably but not extremely larger, takes up the gray of the dome/cone and covers the canvas with it. It is in fact a "blowup" of a portion of the first painting revealing, as in a blowup of one of those famous UFO evidence photographs, a hitherto unseen second UFO hovering against the mysterious gray dome/cone. What represented a tree in the first painting's foreground is enlarged and, as we see the graininess in a blown-up detail of a photograph, the "tree" is seen now as a number of disjointed brushstrokes (themselves of course made up of brushstrokes). And in the texture of these blown-up brushstrokes are more hints at faked pareidolia, though less definable here - some figure eights or infinity signs? is that the word "Hi"? maybe the outline of a bird?
It's a witticism of course, a joke, a sort of juvenile (he was very young when he painted them after all) meta-ness, but/and so as to be a kind of commentary or at least call for commentary on evidence and belief and truth. I like having them on my walls because I go back and forth on whether I think they're deep or dumb, and whether I "agree" with them or find them offensive - especially considering I personally hold to be true many things my brother thinks are crazy "conspiracy theories" based on nothing more than blown-up brushstrokes and (perhaps, planted) pareidolia. But they're also a reminder, to think, in general. I also like having them because I like my brother even though he's annoying.