Many Zodiac Killer enthusiasts have questioned over the last sixteen years whether the imagery on the original American Greetings card was altered by the sender of the communication. These individuals have considered that the Zodiac Killer may have manipulated the snowman to look like Groucho Marx, because he was cast as Ko-Ko in The Mikado, reciting both A More Humane Mikado and As Some Day it May Happen, two Gilbert & Sullivan acts used by the Zodiac Killer in his Little List letter mailed on July 26th 1970.
The designer of the card was George Schill, a contract artist with the American Greetings Card Company (Corporation) for 38 years, who informed me that all the imagery on the card (including the snowman) is exactly as he created it. In other words, nothing was added to the card outer by the Zodiac Killer. George, who retired several years ago, remarked "I did create the card as shown" and that "The ‘“guess who“ copy is typical of a greeting card friendship/secret admirer type of card, and I added the Groucho Marx glasses which are cliche". George's website lists his accomplishments as an illustrator, stating "my work has garnered a number of awards and has been selected for inclusion in the NY Society of Illustrators Annuals, Communication Arts, Printʼs Regional Design Annuals, and the Addyʼs. In addition to my freelance work, I have designed thousands of greeting cards as a contract artist with the humor divisions at American Greetings, where I also write gags, develop characters, and concept new lines. Several of my cards have been nominated for the National Cartoonist Society Reuben Award".
I would like to thank George for supplying me with this information and clearing up some of the outstanding questions regarding the design of the Eureka card. You can visit George's website at https://www.georgeschill.com/