A COUPLE of Dutchmen have strung up a couple of pianos in the great hall of the National Building Museum. From time to time they play them, and the rest of the time the pianos hang there and play themselves, sort of, electrically.

Paul Panhuysen and Johan Goedhart claim that this is art, and it probably is. There's no question that it's fun. I mean, there are these two gleaming grand pianos, vibrating gently just above the floor of Washington's grandest interior space, suspended in a vast spider web spun of 2,800 feet of bright yellow polypropylene rope.

And then there's the piano wire, a couple of thousand feet of it, stretched from end to end of the hall and acoustically coupled to the piano sounding boards, so that they resonate eeeeeeerily. There are tin cans strung on the wire, to tune them or something. Panhuysen, continued on next page from previous page 55, explained this, but I didn't get it. He used to be an urban planner before he became an urban space spanner, and deals in concepts not readily understood by ordinary persons.

The two artists have been doing installation art all over Europe and North America for a decade, and they take it -- but happily, not themselves -- very seriously. This work, sponsored by the Washington Project for the Arts, is their biggest yet. It's elegant and funny -- why do pianos make such great comic props? -- and makes one hope that they'll come back next spring and turn the Washington Monument into a maypole.