  We introduce the concept of a metasurface system able to route space wave via
surface waves. This concept may be used to laterally shift or modulate the beam
width of scattered waves. We propose two corresponding synthesis techniques,
one that is exact but leads to practically challenging material parameters and
one that is approximate but leads to simpler material parameters. The concept
is experimentally verified in an electromagnetic periscope. Additionally, we
propose two other potential applications namely a beam expander and a
multi-wave refractor.
