【明報專訊】This is a figurative way of saying it is impossible for someone to change his basic nature. He or she is what he or she is, and there is nothing to be done about it. "It appears in the Bible, and I think it's a colourful expression," Robert said. But though it's true that a leopard cannot change his spots, Robert is doing a little altering with his paint brush. "There's no harm in trying," the leopard said.