CH3 - CH(CH3) - CH2 - CH2 - CH3
CH3 - CH2 - CH(CH3) - CH2 - CH2 - CH3
CH3 - CH2 - CH2 - CH(CH3) - CH2 - CH2 - CH3
CH3 - CH2 - C(CH3)(CH2 - CH3) - CH2 - CH2 - CH3
CH 3 - CH2 - CH(CH2-CH3)-CH2 - CH2 - CH3
CH3 - CH2 - CH(CH3) - CH(CH2 - CH3)-CH2 - CH2 - CH3