I think this prototol is an atomic one, and is very generative and needs our attention. So let me mention why I named it the pebble protocol in my versions, and the story is also a great example based explaination of what it is.
"After overhearing their parents' plan to abandon them in the forest, Hansel sneaks out and gathers shiny white pebbles. As they are led into the woods the next day, he drops them along the path.
Following the Moonlight: Once night falls, the white pebbles shine in the moonlight, allowing the children to follow the trail directly back to their house" - Wikipedia.
"The story is often remembered for a second, failed attempt. When their parents try to abandon them again, Hansel is locked in the house and cannot gather more pebbles. He tries to use breadcrumbs instead, but birds eat the trail, leaving them lost and leading them to the famous gingerbread house." - Gemini.