Contemporary HO scale (close to 1/8"=1'-0" for architectural models) monopole cantilever double-sided "Bulletin"-size (12'x48') billboard. Billboard panels are available separately, or can easily be made from scratch (come on, it's all rectangular).
This standard design could be found throughout the United States from the early 1970s to the present day. This one is based specifically on a number of signs in San Francisco that were built to be double-sided, but are currently used on only one side. This appearance exposes the detailed structure of the sign toward the back. It is not uncommon for these structures to be seen without panels due to maintenance, or economic downturns.
Originally, the modular panels on the billboard were hand-painted at by the billboard company and bolted together onto the structure. Starting in the 80s, billboards of this size started to use large-scale paper prints pasted to the panels, but these proved to be susceptible to peeling from wind and rain. By the late 90s, the images were printed on large vinyl sheets stretched over the billboard's panels and held on to the steel structure behind with straps, ropes, and elastic cords.
The model is designed to fit over a 1/4" dowel or rod embedded at least 1" into a sturdy base and extending up vertically for 2 1/4". Ideally, the dowel would have a tapered end to ease assembly. Attaching the lights will require 8pcs of 0.015" wire 0.75" long.