The sidewalk chalk in Park Slope has stopped being polite and started getting real

PHOTO VIA NINEDAVESI won't pretend to be smart enough to have any idea what the hell the above sidewalk chalk art really means. I spotted it on Sunday between 5th and 6th ave, near the similarly named 5th and 6th streets  (I was fighting a mean hangover by that point. You can't expect me to remember the exact location). Clearly it has something to do with "House Prices." But what is that y-axis supposed to be? Years? Blocks in Park Slope? Number of children living in the house? My god, would it have killed the artist to provide some more information!? Like, you took all the time to color within the lines. At least give me some discription.

Meanwhile, later that day, I saw another serious sidewalk chalk message (this time on 3rd Street between 4th and 5th Avenue) that simply said, "YOU ARE NOT ALONE." I would have taken a photo, but I was devouring Culture at that point, so I was pretty busy. But dammit, Park Slope -- why'd you have to get all deep on me like this? Whatever happened to drawing rainbows or writing directions to your stoop sale? Isn't that what sidewalk chalk is really for?

Anyone see any other heavy sidewalk art these days? And please -- tell me what the fuck that graph is supposed to be about.