This is part of the wall surrounding the construction site of the Ever Sky Tower, one of the Kotesashi Towers (there are two being built).
I don't know about construction sites in other countries, but here in Japan the construction company usually decorates the outer side of the wall. Some draw trees or flowers and sometimes they show old pictures of the area and have information about the history of the area.
Around the Ever Sky Tower, there are pictures and dates of events related to Kotesashi Station. It was fun seeing old pictures and leaning about how the station came about.
(1970 - Kotesashi Station Opens)
(1977 - The 2000 Type Train is Introduced on the Seibu Line)
(1976 - Construction of Kotesashi Heights Starts)