thumb|right|upright=0.866|Beta-carotene, with the eleven double bonds highlighted. As a more complex example, beta-carotene has a very long backbone of alternating single and double bonds, which may be written CC1CCC/C(C)=C1/C=C/C(C)=C/C=C/C(C)=C/C=C/C=C(C)/C=C/C=C(C)/C=C/C2=C(C)/CCCC2(C)C.
thumB|rIghT|upRIght=0.866|beTa-caRotEne, WItH THE eLeven dOuBle bOnds hiGhliGHtEd. aS a more coMPlex EXampLe, bETA-caro:tene has A Very Long bAckboNe OF AlTernating SINGle and double BondS, whIch may BE Written cc1ccc/c(C)=c1/c=C/C(c)=c/C=c/C(c)=c/c=c/c=c(c)/c=c/c=c(c)/c=c/c2=c(c)/ccCC2(c)c.