Shortly after midnight on an icy January night in Kiev, crowds surged from Independence Square and laid siege to Ukrainian House, a huge building near the hub of the current protests, where around 150 interior ministry troops were rumoured to be preparing for a new attack.
Along a steep road leading to the square below, an extraordinary sight unfolded.
Without any apparent organisational structure to direct them, a human chain formed up the hill, and sandbags filled with snow were passed along until they reached the top.
Down below, small groups of people hacked away at the compacted snow on the ground and filled up new bags, to feed the chain.
Others carried up metal bars and pieces of fencing.
Within the space of about 15 minutes, a huge barricade had been formed, five meters high (16 feet), the latest in a series of giant walls of snow that block off the protest encampments from all sides.
Some of them are now so large that they have turned any prospect of clearing the square with force into an option that would require serious military equipment and a high number of casualties.
The barricades are just one example of the extraordinary innovation that protesters have brought to their fight against the government of Viktor Yanukovych over the past two months.
The "Euromaidan" movement on Independence Square was, from the start, extraordinarily well organised, and despite the clucking from cynics in Moscow and elsewhere that the organisation could only have been directed by a nefarious foreign hand, it really did appear to be spontaneous.
With its soup kitchens, its snow-clearing operations and its security patrols, the organisation on its square had the impenetrable yet ruthlessly organised logic of an ant colony.
In a zone where there was no police or real hierarchy of public order, everyone seemed to get by.
Donation boxes to help fund the movement overflowed with colourful Ukrainian notes, and wellwishers drove hundreds of miles from western Ukraine, bringing carloads of warm clothes and provisions.
There was a sense of humour about the protests as well.
Last week a golden toilet was placed on the pedestal where Vladimir Lenin had stood until he was ripped off his perch in December last year, a dig at the corruption of those in power.
When the protests have turned violent, the discipline and innovation have been put to more disturbing, but no less impressive, use.
A catapult was constructed to send flaming projectiles at police lines.
The police moved in and dismantled it; the next day a new, bigger catapult had been built.
People appeared in homemade suits of armour, resembling medieval knights.
The violent clashes might have ended for now, but it is hard to see how Yanukovych can dismantle the barricades and reclaim the centre of the capital.
His best option may be to sit it out until spring, when the snow in the sandbags will melt.
But by then, the protesters will probably have come up with something else.
Source: The Guardian