  We present a complete theory of bicircular high-order-harmonic emission from
N-fold rotationally symmetric molecules. Using a rotating frame of reference we
predict the complete structure of the high-order-harmonic spectra for arbitrary
driving frequency ratios and show how molecular symmetries can be directly
identified from the harmonic signal. Our findings reveal that a characteristic
fingerprint of rotational molecular symmetries can be universally observed in
the ultrafast response of molecules to strong bicircular fields.
