For months, curators at a British museum had been wondering how an ancient Egyptian statue in a sealed display cabinet had been able to rotate on its glass shelf, seemingly of its own free will.
Rumours abounded that it was cursed by an Egyptian god, or that the spirit of its owner had entered the figurine, causing it to shudder. Others put forward more prosaic explanations, suggesting a magnetic field was behind the statue's movements.
But now, a British engineer has solved the riddle, discovering that miniscule vibrations from traffic and footsteps from passersby were causing the 3,800-year-old stone figurine to spin.
"The statue was rotating due to vibrations entering the display case," Steve Gosling told Reuters by telephone on Wednesday. "We installed an accelerometer and found that vibrations from both road traffic and footfall within the museum were the cause."
Video footage of the spinning statue went viral on the Internet over the summer, drawing crowds to the Manchester Museum in northern England to gaze at the curious artefact.
Gosling, who made his discovery as part of an ITV television series called "Mystery Maps", said the bulk of the weight of the 25 cm statue was at one end, meaning it was off-balance and especially susceptible to vibrations.
"With an object of such hard material on a glass shelf, the level of friction between the two materials is very low. It doesn't take a lot to make it move," he said.
The statue, of a man called Neb-Senu, was intended as an offering to Osiris, ancient Egyptian god of the dead and ruler of the underworld. It was donated to the museum by a private collector some 80 years ago.