The familiar sound resonates through the calm environment of a home, creating a sense of anticipation. It's the sound of a door being knocked on. The distinctive rhythm of the knock echoes against the sturdy material of the front door, a portal that separates the comfort of the inside of a house from the outside world. This is a common occurrence in a house, yet each knock brings with it a different sense of curiosity and expectation. The knock on the door, in the peaceful setting of a home, interrupts the tranquility for a moment, signaling the arrival of someone or something, and altering the course of the day.