It was created by a group of students at an urban university in a country where the legal age to drink alcohol is 18. Such conditions often lead to collections of traffic cones.
So if it had been made 10 years earlier it might have featured a traffic cone AND a shopping trolley!
This story involves drinking students and internal jokes :)
Why not ask something that isn't in the Wikipedia article?
All I get is that it's an "in joke" of sorts that has just never changed. What I'm asking is: is there anything more than that? Such as: why hasn't it changed (not that it should)?