Dot plot (left) and mfe structure representation (right) of the cofolding structure of the two RNA molecules AUGAAGAUGA (red) and CUGUCUGUCUUGAGACA (blue). Dot Plot: Upper right: Partition function. The area of the squares is proportional to the corresponding pair probabilities. Lower left: Minimum free energy structure. The two lines forming a cross indicate the cut point, intermolecular base pairs are depicted in the green upper right (partition function) and lower left (mfe) rectangle.