We report the formation of “ripple” patterns by the sequential superposition of nonorthogonal surface
waves excited by the spontaneous buckling of polymeric bilayers. Albeit of a different nature and micron
scale compared to the familiar sedimentary ripples caused by gentle wave oscillations, we find
commonalities in their topography, defects, and bifurcations. The patterns are rationalized in terms of
a defect density that depends on the relative angle between generations, and a constant in-plane bending
angle that depends on skin thickness. A minimal wave summation model enables the design of ripple and
checkerboard surfaces by tuning material properties and fabrication process.