National Educational Television logos (1957/1960) [closing plaster]
From episode one of WTTW Chicago's "Searchlights on Delinquency"; the 1959 "NET House" makes a surprise appearance at the end (the source was a rerun print from 1960).
Credit goes to the American Archive of Public Broadcasting: this and many more can be found in their NET collection at: https://americanarchive.org/special_c...