Thieves stole two trailers from an autonomous trucking company, including one emblazoned with Nvidia’s logo. Their haul? 40,000 pounds of sand.

The trailers were reported stolen overnight on Thursday from PlusAI, which uses Nvidia chips in its self-driving systems. Rather than carrying Nvidia’s valuable AI chips, known as GPUs, each trailer was filled with sand. PlusAI vice president of marketing Lauren Kwan said the company uses sand to simulate cargo weight during test drives.

Kwan said that hours after the company discovered the trailers had been stolen, a friend of a PlusAI employee spotted them parked near another company’s office…