  Metamaterials with the transformation method has greatly promoted the
development in achieving invisibility and illusion for various classical waves.
However, the requirement of tailor-made bulk materials and extreme constitutive
parameters associated to illusion designs hampers its further progress.
Inspired by recent demonstrations of metasurfaces in achieving reduced versions
of electromagnetic cloaks, we propose and experimentally demonstrate source
illusion devices to manipulate flexural waves using metasurfaces. The approach
is particularly useful for elastic waves due to the lack of form-invariance in
usual transformation methods. We demonstrate metasurfaces for shifting,
transforming and splitting a point source with "space-coiling" structures. The
effects are found to be broadband and robust against a change of source
position, with agreement from numerical simulations and Huygens-Fresnel theory.
The proposed approach provides an avenue to generically manipulate guided
elastic waves in solids, and is potentially useful for applications such as
non-destructive testing, enhanced sensing and imaging.
