define ~carbonA (carbon and ~chainA) define ~carbonB (carbon and ~chainB) define ~hydCHA (hydrogen and ~chainA and within(1.2,carbon)) define ~hydCHB (hydrogen and ~chainB and within(1.2,carbon)) select all connect 3.0 4.0 (~carbonA) (~hydCHB) hbond create connect 3.0 4.0 (~carbonB) (~hydCHA) hbond create select ~carbonA, ~carbonB, ~hydCHB, ~hydCHA hbonds on hbonds 0.2 color hbonds pink