Simulation
confirms ray-like propagation
Extra force is applied at ¥ and measured at ––––
No force above ¥, as predicted
Unlike elastic material
Force beneath is maximal in
oblique direction
Not directly below ¥
Locus of max force is along oblique rays
Averaged over 100 cases
Dx/Dy
Alexei V. Tkachenko, TW, (2000)