The sight of two strings and a bucket overhead sparked confusion among residents in Paisley, Renfrewshire, last week.
But it has now emerged that a group of students were using the system to pass items including cups of tea, biscuits and even a bottle of milk without leaving their homes.
Three flights of stairs down, a short walk across a road, and another two flights of stairs up proved to be too strenuous for them.
So they used the contraption which is more commonly associated with wells or building sites.
Jamie Stewart, Josh Still, Josh White and Ewen MacKenzie have lived opposite each other for two months and joked about creating a way to pass things between the houses.
The bucket pulley was up for just a few days before spoilsport residents raised the alarm and police told the students to take it down.
Psychology student Ewen, 21, bought the string and bucket from Home Bargains before setting it up.
His flat mate Jamie said that they had been discussing the idea for a while.
Jamie, 19, said: "It wasn't that surprising when Ewen came home with the string and the bucket, we'd been talking about it for a while. We were just having a bit of a laugh."
Neighbour Graham Yuill, 49, noticed the bucket going between the houses in the evenings and managed to catch a snap of it in action.
He said: "If it can happen, it will happen. What happens if it tumbles and an object hits a car?
"The person who did it won't admit it. Secondly, if they drop glass you've got dogs who could cut their paws on it.
"Also, what if it hits somebody in the head? It can give someone serious head injuries. While there is a funny side, I always think what happens if."
The students saw Graham taking the photo and said that they had been sending eggs over to Ewen who was in the middle of making a fry-up.
He added: "I think the first time we used it Ewen said he'd left his wallet and he couldn't be bothered to come and get it so we said 'Don't worry Ewen, we'll send it right over.'"
The marketing student at the University of the West of Scotland said he was surprised that the bucket had gained any attention.
The four boys used two strings to move the bucket between the houses on Townhead Terrace.
A white string, which the bucket moved along, and a red one, which they pulled to make the bucket move between their windows.
The daring students had to use the cover of darkness to get the pulley system into place by standing in the middle of the road and throwing one end of the string into the open lower window.
The other students held onto the string in the other window and put the bucket onto the white string.