The observer in the world of three dimensions can see the crags, fissures and flow of the now-hardened concrete pictured below. In the pancake-flat world of Flatland, none of this can be seen. However, Flatlanders may be able to experience the roughness of the underlying forces that can only be revealed in a third dimension.  How are these 3-D forces experienced in 2-D?

A Great Disturbance
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