A production system includes a first reaction chamber and a second reaction chamber. The first reaction chamber is configured to receive a first hydrocarbon stream therein through an input port and to form carbon seeds and hydrogen gas therein via hydrocarbon pyrolysis of the first hydrocarbon stream. The second reaction chamber includes a first input port and a second input port. The second reaction chamber is configured to receive the carbon seeds through the first input port and a second hydrocarbon stream through the second input port, and to form carbon product elements and additional hydrogen gas in the second reaction chamber via hydrocarbon pyrolysis of the second hydrocarbon stream. The carbon product elements represent the carbon seeds with additional carbon structure grown on the carbon seeds.