The triangle wasn't the only Nazi reference. They ran 88 variations of the ad, and the first sentence had 14 words. Both numbers are well-known references used by neo-Nazis for decades.

https://en.wikipedia.org/wiki/88_Precepts

https://en.wikipedia.org/wiki/Fourteen_Words

edit: If anyone doesn't believe that "14 words" is a neo-Nazi dog-whistle, here's the Anti-Defamation League's explanation:

https://www.adl.org/education/references/hate-symbols/14-wor...