We have these windows in our exterior doors, but they aren't like regular windows that you can just look through. I don't know what they're called. They are in "sections" like stained glass, but the glass isn't colored. Some of the glass is etched and some is just lumpy. I did briefly try to sort this out on the Google, but I got nothing. Anyway, the point is that light shines through these doors, but in scattered patches. The other point is that Baby Grady finds this fascinating.
He chases those light patches around and tries to grab at them. Sometimes he even tastes them. Which is just a really sensible thing to do when you are faced with such wonder, I think. He always peels back the rug, driving Jasper batty, looking for the source of those wily light patches. Or maybe trying to better comprehend their behavior. I don't really know.
He hasn't managed to grab one yet.
But he's still working on it.