There is also a secret code meaning between us, which represents some private content between us. When we are outside or chatting with others, we only need a trivial action to remember each other's existence and importance. This secret code is not only a symbol, but also a tacit understanding and trust between us.
Although 624 is just a simple number, it has far-reaching significance to our feelings. After all, in a relationship, two people need not only romance and passion, but also mutual understanding and support. In our world, 624 is the tacit understanding and bond between us, which makes us more tacit understanding and firm.