This is an installation that's relatively easy to do. Take some rocks and place them along a fallen tree. If you live in an environment bereft of fallen trees, you could run a line of rocks along the base of a fence, or in the middle of an alley, or on a railing.

Gradually, or quickly, something or someone will remove these rocks. The example shown above was installed along a creek bed. Next time we get a big storm, many of the rocks will be washed away.

Christo's "Gates" installation in Central Park, NYC, got me thinking about less expensive, easier installations of a subtly less monumental nature that could be accomplished in an afternoon and without cost. Christo's installations cost millions of dollars, which does add to the impressiveness of the piece, but as there are grand installations there is room for small, simple, improvised installations. In the case of the installation above, probably no one will come across it. It's in a fairly untraveled portion of a forest, not near any trail.

If an installation went up in the forest, and no one saw it, would it still be an installation?