The Morse code in music thread had me thinking about Morse Code in Print and I seem to remember seeing it in Mad Magazine in the past.
Even though I was an avid collector and own many of the older back issues, I had to look up where I've seen it.
It is in the Spy vs. Spy series by Artist/Writer Antonio Prohías. The series of dashes and dots is Morse Code for "By Prohias"

en.wikipedia.org
More ham references in Mad Magazine:
www.onallbands.com
Share your Morse Code in Print references if you have them.
Even though I was an avid collector and own many of the older back issues, I had to look up where I've seen it.
It is in the Spy vs. Spy series by Artist/Writer Antonio Prohías. The series of dashes and dots is Morse Code for "By Prohias"

Spy vs. Spy - Wikipedia
More ham references in Mad Magazine:
Ham Radio and Morse Code in Popular Culture: MAD, 73 Magazine, and Remembering Artist Wayne Pierce, K3SUK (SK)
Amateur operator Jeffrey Swain Makes Sure His Mentor’s Callsign, K3SUK, Lives on. Once upon a time, American teenagers—and plenty of adults with subversive tendencies—turned to MAD magazine every month for […]
Share your Morse Code in Print references if you have them.