Echo fun

If you go to the edge of a certain field in Galloway, Scotland, you will encounter the ‘Echo Barn’- see link 1. Shout from the right place, and a little while later your yell returns as a clear echo.

There were military sound mirrors in WWII which were used to assist early detection of the approach of enemy aircraft. (Link 2)

This reminded me of [lankybits]'s idea, link 3.

I propose that, for a bit of fun, you stand on a platform. In front of you are a series of buildings. The walls facing you are spaced at distances about 150m further away in sequence. The more distant buildings will be larger as required.

You could stand here, make an outburst, and hear it repeated back at approximately one-second intervals; tee hee!

The walls of the buildings are slightly concave. They have a common centre of curvature at the point at which you stand, to ensure that the wavefront reflections exactly converge back to you.