In a method for synthesizing a long nucleic acid molecule, a first immobilized nucleic acid has a first 5′ region and a first 3′ region and a second immobilized nucleic acid has a second 5′ region and a second 3′ region. The second 3′ region and the first 5′ region have identical nucleic acid sequences. An oligonucleotide is hybridized to the first 3′ region, extending the hybridized oligonucleotide and producing a first extension product having a 3′ region that is complementary to the first 5′ region. The 3′ region of the first extension product is hybridized to the second 3′ region, extending the 3′ region of the first extension product and producing a synthesized nucleic acid molecule having a 3′ region that is complementary to the second 5′ region, wherein the synthesized nucleic acid molecule has a sequence complementary to the first and second 3′ and 5′ regions.