If object A sent the message “1” to object B, object B would need a “mailbox” with “1” to actually receive this message. Correct? Well, if Object B had 2 Mailboxes with the message “1”, only 1 “mailbox” would actually trigger. If an object could receive multiple messages, it would cut down on the amount of wires that could overlap. Just my opinion, I’m still learning how to simplify things though…