these colorful windshield decals from the 1920s and 1930s were found tucked into photograph album pages within the William M. McCarthy Photograph Collection at the California State Archives.

https://www.facebook.com/CaliforniaArchives/posts/pfbid02NEsV1zPH4YcP8fCVcuJfzfsHRZVq9hcJ1jqBrdjkMdvmMLoYiwniVLLuY4wNBSfnl

https://exhibits.sos.ca.gov/s/exhibits/item?sort_order=desc&fulltext_search=National%20Park%20Service&item_set_id%5B0%5D=4&submit=Search&page=2