A stamping press, which produced the automobile fender held by the workman on the left, is represented in this portion of the mural. Flat sheets of steel were fed to the die. The upper and lower sections of the die came in contact and held the sheet, while the center section (called the punch) formed the shape of the body part. Air was released with each pressing operation, which is why Rivera painted the press operator with his hair standing on end.

It is clear that Rivera painted his press to actual scale. The only portion altered in the mural is the electric motor housing at the top. This part of the actual press was very small and in a somewhat ovoid shape. Rivera transformed his motor housing into a mechanical head complete with eyes and ears and placed it on top of the press, which he saw as a giant mechanical body. This press has been anthropomorphized more than any other machine in the mural cycle and is analogous in form to monumental sculptures of Pre-Columbian deities. Here, Rivera compared the tremendous physical force of the press with the cosmic force of the supernatural.

Rivera adapted many of his images from the Pre-Columbian art of Mexico. Among them are the Aztec pyramid in the center of the top register of the south wall and the half-face/half-skull on the west wall, taken from Tlatlico sculpture. Rivera also slightly altered the two rows of multiple spindles on the north wall to correspond to the monumental sculptural form of Aztec gods.

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