BEIJING — For more than a minute on Tuesday night, nine-digit numbers were displayed across the facade of Hong Kong’s tallest skyscraper, the International Commerce Center. Towering above Victoria Harbor, the glowing white digits blinked against the night sky: 979,012,493… 979,012,492… 979,012,491…

The seemingly innocuous numbers contained a subversive statement. The animation is a countdown of the seconds until when the “one country, two systems” framework — a guarantee that Hong Kong, a former British colony, would keep its civil liberties and a high degree of autonomy for 50 years after its return to Chinese sovereignty in 1997 — is set to expire.

“We hope to deliver this work to illustrate the biggest anxiety of the Hong Kong people,” Sampson Wong, who created the animation with the artist Jason Lam, said before the lights first went up.

The artists planned the display to coincide with a three-day visit to Hong Kong by Zhang Dejiang, a member of China’s governing Politburo Standing Committee, which began on Tuesday. Mr. Zhang is the highest-ranking official from mainland China to visit Hong Kong since the pro-democracy demonstrations in 2014 known as the Umbrella Movement.