Corner of NW Cass Avenue and W Forest

Hello! Hoping someone can assist me. I have been tasked with trying to find out the significance, if any, of the elements that look like they were set into this decorative wall.
Here is what I know. This is the NW corner of Cass Avenue and W Forest. The home that was here was 4715 Cass, torn down for a parking lot in 1971 or so. The parking lot that was installed in 1973 shows the wall, but no other information than that. Does anyone have a photo, or know where these came from? Thank you!Attachment 36031