What do two cats mean on Nanchang Bayi Bridge?

The Bayi Bridge, which spans the north and south banks of the Ganjiang River, is magnificent. There are two mighty stone lion sculptures at the northern end of the bridge, which mean "emancipating the mind and seeking truth from facts" (lions, thinking and things are similar in homonym). Interestingly, at the southern end of the bridge, there are two sculptures of cats, one black and one white. The black cat still has a mouse in its paw, and the mouse has a copper coin in its hand. The white cat jumped up and down, ready to pounce on the prey in the hands of the black cat. Here is a little story that I don't know whether it is true or not: a leader of the central government visited Nanchang, and the Bayi Bridge has not been fully completed. The great leader saw the stone lion at the northern end of the bridge for the first time and was very satisfied. He asked local officials, "Is there such a stone lion at the other end of the bridge?" Local officials said in Mandarin with a strong dialect, "Not yet." The big leader heard that it was a "black cat". Immediately, I even thought of the famous saying of the chief designer, "No matter whether it is a white cat or a black cat, as long as it catches mice, it is a good cat." He said to the local officials, "Why not put a white cat and a black cat there?" Local officials repeatedly said yes, so there was a bridge and two cats, one black and one white.