In this contribution we have considered fusion reaction of carbon clusters obtained from the natural blocks of sumanene. We obtained four natural isomers of fullerene C60. Together with the fifth natural isomer found elsewhere through the use of the Endo-Kroto mechanism (dimer embedding model), now we have the structure of all the experimentally observed isomers of fullerene C60. One isomer is a perfect, the other are imperfect and differ in the number of pairs of two adjacent pentagons.