"There's still one more park taboo to be broken."

Dan Graham’s mirrored glass pavilion on the rooftop of the Met is a beautiful thing. A steel-framed S-curve, set between two parallel “hedges” made of ivy; it invites wandering and looking on a surprisingly small footprint. The two-way glass reflects you, the greenery and the surrounding city in unexpected ways, with the borrowed landscape of Central Park reverberating its leafy walls.

But the pavilion is not the only element that borrows landscape. Graham worked with landscape architect Gunther Vogt on the rooftop; together they surrounded the rectangle of ivy, glass and stone with a padded, brilliant carpet of artificial turf, from edge to edge. On the sunny day I visited, people were lying all over that turf, attaching themselves to the entrance trellis and ivy walls as if they were trees in the park. The soft surface gave them permission to sit anywhere. I couldn’t decide though, was the effect ersatz park or rumpus room? Did it make the rooftop into a greensward or a really groovy basement? After all, the first artificial lawn many of us saw was in the Brady Bunch’s backyard. Mike Brady, paterfamilias and architect, knew a real lawn wouldn’t last long under the kids’ 12 feet.

AstroTurf (or ForeverLawn, or SynLawn – pick your brand name) at the Met felt like a moment. A moment in which we might be able to give up, at least in high-traffic urban settings, on our trophy grass.