A student posted a photo on Reddit  and Imgur of David Lydic flashing the shirt this week, with the caption, "Frustrated with the same old questions, my professor ripped off his shirt in the middle of lecture." It quickly was posted to other social media, prompting hundreds of comments from students and strangers alike, including: "As a TA for a class of roughly 200 mostly-freshmen... I need this" and "Heisenberg!," a reference to the alter ego of Walter White, the chemistry-teacher-turned methamphetamine dealer in the hit TV series "Breaking Bad."
Lydic said in an e-mail that he's been using the shirt for several years, but students' photos of him wearing it never made it further than Facebook, until now.
"No particular question prompts its use," he said. "Every semester I get routine questions that are answered in the syllabus. So every semester about halfway through I put it on and do my schtick about reading the syllabus."
He described his "schtick":
"I say this to the students: 'I've been asked a lot of questions lately that you should know the answer to: Was today the deadline? When is the next quiz? How are grades figured? What are your office hours? And my favorite, 'Do you have an office around here?' (No, I just wander around the neighborhood. I hope you can find me when you need me.) As the semester heats up and time gets short, I don't want you to get in trouble because you didn't know something you should have. (By now I'm unbuttoning my shirt.) I'm here to remind you that 'It's in the syllabus.' Shirt opens."
Students always laugh, and it's a quick, effective lesson in reading the syllabus before asking questions, he said.
But Lydic can't take all the credit. He said he bought the T-shirt several years ago at a conference hosted by his friend, Amy Baldwin, a professor of English at Pulaski Technical College, in Arkansas. An author of numerous books on student success, her website is called It's in the Syllabus. 
Baldwin said in an e-mail that she made the shirts -- available for purchase on her site -- several years ago after a student in her class told another student who'd asked about a paper due date, "It's in the syllabus!" The class laughed, she said, but she hoped wearing the message would help students "see the syllabus as an empowerment tool, something that provides a roadmap for them to success. I know I certainly create my syllabus with that intention."
Lydic noted that he wasn't actually angry when the photo was taken, as some commenters have guessed, but just posing for a student who said "'But you don't look mean enough.' You see the result of my response."