Tangible Sandbox Map
The projected image changes as the sand it is projected on changes. Screenshot by author, from YouTube

Today’s battlefields change in the blink of an eye. Generally, that’s because of new attackers emerging from somewhere unseen, or an undetected bomb going off, but what if the sudden change instead came from a burst dam or flash flood? To answer these questions, and prepare for future wars, the Pentagon is playing in a literal sandbox.

From Nextgov:

The sandbox, built with kinetic sand, a projector, and a depth-detecting camera (possibly a Kinect) allows planners to see a physical landscape and then change it, with newly formed depressions and valleys showing how water could flow through the entirement. That’s good for modelling sudden floods and new hazards. Better to do it with this sandbox than experience it first-hand.