Egyptians have been glued to their televisions these past few weeks, as footage of fighting between protesters and security forces showed the fiery arcs of Molotov cocktails crashing on to the street, batons striking demonstrators and blood-streaked pavements.
But few things have confirmed Egypt is in the throes of a "second revolution" as the four five-metre concrete walls and razor-wire fencing around Tahrir Square, the ministry of interior and Qasr Al Aini Street.
Much of downtown is now a militarised zone, with the risk of police or army raids on gatherings as far away from Tahrir as Taalat Harb square, a five-minute walk away, and the cabinet building, about the same distance.
Through the chinks in the concrete blocks, phalanxes of soldiers and police can be seen wearing riot gear.
The Supreme Council of the Armed Forces (Scaf) has said these walls were to protect government buildings from would-be saboteurs and to cease clashes with protesters.
On the ground, though, it feels like the exasperated and often inept military rulers are ceding Tahrir Square - the centre of the uprising in January and February that forced Hosni Mubarak from power - to the movement opposing their stewardship.
The divisions in the country just nine months after the uprising are at risk of being cemented in place.
In the first confrontations between security forces and protesters after Mr Mubarak stepped down in February, police used early-morning raids to clear the square. The refrain from the interim rulers at the time was that the people refusing to leave were disrupting traffic and hurting the country's economy.
Over time, as the protests gathered steam, Scaf appeared to have given up hope of controlling the square, without resorting to walling it in.
The first sign of this came with a concrete wall built on Mohammed Mahmoud Street, home to the downtown campus of the American University of Cairo, in late November after more than 40 civilians died and thousands were injured in clashes with the police.
By yesterday, three entrances to Tahrir Square had been sealed off by the military. Qasr Al Aini Street, a major traffic artery, was completely blocked, as was Sheikh Rehan Street aside the now burnt-out Institut D'Egypt building.
Ibrahim Eissa, the iconoclastic editor of Al Tahrir newspaper, wrote in a column yesterday the concrete walls were a metaphor for Scaf's approach to its opponents.
"The army puts a concrete wall between itself and the revolutionaries, which confirms its failure," he wrote in an edition that featured on its front page a photograph of a young veiled woman being beaten and stripped superimposed on a picture of a Scaf press conference where generals said they were protecting the country against saboteurs.
"Whenever it has a problem or creates a confrontation, they build a wall," Eissa said, adding the period was now characterised as "the politics of the concrete wall".
The walls "are not just in the streets," Eissa wrote.
"They are also in [Scaf's] head and brain. It is in its heart, against these youth. They don't understand and then they can't stand it, and so they kill them."
Having abandoned for now its attempts to retake the square, Scaf has embarked on an information war. So far, its efforts have paled compared with the round-the-clock work of the activists, who are much more savvy with video equipment and social networking. Dozens of videos have exposed incidents of the military and police beating unarmed protesters and throwing rocks from buildings on to people below.
The physical separation of the two sides - military and police on one side of the barricades, and groups of protesters that swing between scores and thousands - is another attempt by Scaf to marginalise groups that seek to equate it with the brutal Mubarak regime.
Nathan Brown, a professor at Georgetown University who was in Cairo this week, said the events of the past several months have led the military leadership to lose legitimacy among many groups, but the big challenge for the loose opposition is to inspire tens of thousands, if not hundreds of thousands, to come back to the square to force changes.
"How broad that loss of legitimacy becomes depends on what happens next," he said. "If [Scaf] can isolate the protesters and allow the electoral process to continue, they might be able to get away with it."