CH3 - CH2 - C(CH3)(CH3) - CH(CH3) - CH2 - CH2 - C H2- CH2 - CH3
CH3 - C(CH3)(CH3) -C(CH3)(CH3) - CH2 - CH2 - CH3
CH3 - CH2 - C(CH3)(CH3) - CH(CH3) - CH2 - CH2 - C H2- CH2 - CH3
CH3 - C(CH3)(CH3) -C(CH3)(CH3) - CH2 - CH2 - CH3