While classmates were outside enjoying recess, one high-school student in the Siberian village of Tayozhny snuck back into the classroom to leave a public indictment of Russia's longtime president.
"Putin is a thief," the student wrote on the blackboard on November 12.
When Class 10a settled into their seats the next day, they got an earful about the bad old days from their elderly history teacher, Yevdokia Kovalyova.
"Your grades have slipped, not to mention your behavior," Kovalyova can be seen shouting in a surreptitiously recorded video posted on YouTube. Accusing the class of insulting "our president in the worst way," she noted that such disobedience "would have been punished in the Soviet era with execution by firing squad":
"What has he done for us, for Tayozhny?" a student named Alyona asks.
"Alyona, you weren't here yesterday. You don't know," Kovalyova responds.
"My advice to those who wrote this," she adds, is to "write that phrase, seal it in an envelope, and send it off. Here's the address: Moscow, Kremlin, presidential administration. They'll quickly fly out here and deal with you. Putin has bodyguards!"
Kovalyova's blistering speech predictably went viral, inflaming already heated debates about the generational divide exposed by attempts to mold smartphone-wielding students into compliant, uncritical youths.
The recorded diatribe is only the latest to show students clashing with their Soviet-educated teachers about everything from endemic corruption to the state of provincial towns.
The trend of posting such classroom debates online emerged in early 2017, when teenagers had a strong presence in anticorruption protests that swept the country that March and prompted the Kremlin to rethink its approach toward Russia's youth.
In one early example, a student in Bryansk was detained in class after he promoted an upcoming protest rally on social media. The school's director gave a stern lecture about the dangers of opposition sentiment and the importance of patriotism.
Shortly after that incident, a lecturer at Tomsk State University was filmed relaying the sentiments of a former KGB chief in telling his class: "If there's no corruption in government, that government is no use to anyone":
Those who attend protests are "freaks," he added, alleging that participants were paid and suggesting they should find a better way to earn money.
The same week, at a nearby high school, teachers gave a lecture about the similarities between liberalism and fascism, and called students who protest "fascists" and "traitors":
And at Vladimir State University, students were brought to a lecture hall and shown a video comparing opposition leader and anticorruption campaigner Aleksei Navalny, who was spearheading the March protests, to Hitler:
"A full-on war is being waged against the Russian Federation," the school director told students after the screening. "And it's targeting the youth."
There's no evidence that the admonishments are not solely the initiative of the teachers themselves, but the Kremlin does appear to be playing a hidden hand.
In May, in a bid to temper dissent among the youth, a saucy music video was released featuring half-naked women and pop star Alisa Vox seducing a schoolboy, who bows his head in apparent shame for participating in protests:
The song, titled Baby Boy (Malysh), suggested that Western funding was behind the protests and claimed that youth participation in them comes at the expense of a good education and success in the future. The lyrics warn against attending protests in return for "mountains of gold" and Euros.
On a beautiful sunny day,
To a protest he goes,
With unfirm hands,
He takes up his banner.
Mistakes on the banner,
Four words written as two,
But his heart beats fervently,
And there's anger in his eyes.
Various sources told Russian media at the time that the Kremlin was involved in funding and coordinating the release of the video.
Efforts to counter the opposition protests have let up since Putin's reelection in March. But the government's wariness of youth dissent remains. A bill mandating fines against anyone who encourages children to attend unsanctioned protests is making its way through the legislature, and passed its first reading in the State Duma last week.
The proposed fine would be 30,000 to 50,000 rubles ($450 to $750) or 15 days in jail, and repeat offenders would be treated more severely. If implemented, the law would be just one of the initiatives to emerge in the aftermath of heavy youth involvement in the 2017 protests.