UPDATE: I found it. It was a post by Jay Nordlinger at the Corner. One of his readers wrote in to tell the tale of how the bandanna provoked pro-Holocaust remarks from one of his commie professors. Another reader wrote:
Anyway, I think that wearing or displaying the Star of David is a great way to show support for Israel and to let today’s Nazis know that the Zionist conspiracy is as close as next door or the office across the hall.GREAT IDEA. Perhaps we could generate T shirts and other apparel to show support for Israel. I whipped out my Photoshop and came up with a few suggestions. Here they are.
Left to Right: 1. Here's the simplest idea: Just a white T shirt with a blue Star of David, reminiscent of the Israeli flag.
2. I like this one better: Same T shirt, but with the Hebrew script for Israel added.
3. Here's one with a spicy statement.