But over the course of this week, that friendly face was replaced by the snarling visage of a furious young man hurling gasoline bombs and chunks of pavement at police struggling to contain riots that have turned downtown Barcelona and other towns in the wealthy northeastern region into no-go zones at night.
So the fuse was lit when Spain's Supreme Court on Monday found 12 of the movement's leaders guilty for their role in the referendum. Nine were given nine to 13 years for sedition. With no major leader left on the ground to contain it, the rage exploded — aided by technology that has helped much more loosely organized groups to plan protests and hide their movements from police.
For four successive nights, protests have spiraled out of control come nightfall, with demonstrators burning cars and hundreds of trash cans, causing 1.1-million-euros-worth of damage ($1.2 million) and eventually clashing with police in Barcelona, a leading European tourist destination. Fires also raged in other towns across Catalonia, an industrial powerhouse region that is home to 7.5 million people and has its own language and cultural traditions.
"Catalans tried for a long time to demonstrate to the world that we can achieve significant change through democratic, peaceful means, but we were slapped in the face," Adrià Alsina, the former spokesman of the grassroots pro-independence group ANC, told The Associated Press. "At least the violent movements in France, or Hong Kong, or Ecuador are achieving some of their goals."
"Ever since Monday," he said, "the people who had the moral authority to stop this, they are in jail."
Authorities said that nearly 100 people were injured, almost half of them police officers. A total of 97 protesters have been arrested since Monday, including four sent to jail while authorities investigate them for public disorder.
Police said the protesters hurled gasoline bombs, acid, stones, firecrackers, nails and bottles at them. Fireworks hit a police helicopter, although no major damage was caused. Outnumbered regional and national police responded with foam and rubber bullets, batons and shields. A 17-year-old boy was recovering from a head injury caused when a police van charged into a trash container he was hidden behind in the city of Tarragona. Another protester lost an eye earlier this week.
Images of a father holding his baby after they had to flee their apartment in downtown Barcelona for fear that the flames would reach their building have shaken the city.
"We have to make a call for calm," Barcelona Mayor Ada Colau, who does not support a break with Spain, said on Thursday. "These incidents are causing great concern among the populace."
Peaceful protests like those that long characterized the movement are continuing — including a student strike and marches that are set to converge on Barcelona on Friday. But they are being overshadowed by the chaos.
With the traditional forces in the separatist movement and their calls for a non-violent path to independence losing their luster for many, the spotlight is now on the self-appointed Committees for the Defense of the Republic, a loose network of locally organized activists, as well as a new shadowy group, Tsunami Democratic, which has developed its own app and also uses other messaging services to advocate for "peaceful civil disobedience."
Tsunami Democratic's leaders and operators are not publicly known, though Spanish Interior Minister Fernando Grande-Marlaska said that police are on their trail.
But Puigdemont, who is a fugitive from Spanish justice in Brussels, retweeted a tweet from Tsunami Democratic on the same day as its official launch. Other top separatists followed suit — and Tsunami Democratic's channel in the encrypted messaging app Telegram gained more than 320,000 followers in just over a month.
Puigdemont and other leaders of the movement agreed to endorse the Tsunami Democratic in a meeting in Geneva in July, according to two people with knowledge of the meeting who spoke on condition of anonymity. One was from the orbit of the separatist movement who didn't want his identity revealed because security forces are investigating the group. The other person was familiar with the authorities' probe but was not authorized to reveal details of an ongoing investigation.
Tsunami Democratic was behind the call via Telegram to storm Barcelona's airport on Monday, causing cancellations of some 150 flights and leading to clashes with police late into the night outside the terminal.
The design of the group's own app makes it very difficult for authorities to shut it down, according to Enric Luján, a professor of political science at the University of Barcelona who specializes in the intersection of privacy, digital security and political theory.
The app's security protocol limits scrutiny by those outside the movement by giving each user one access code to share with one new potential user that he or she trusts. Once inside the app, it only informs the user of protests in the vicinity, thus greatly limiting the information any one person has.
"It is creating the perfect storm," said Luján. "It is based on a very decentralized system. You do not know where the central node is."
But he also criticized the fact that the app allows some unknown force to give orders.
Puigdemont's hand-picked successor, Quim Torra, told the Catalan Parliament on Thursday that the only response to Monday's verdict was to hold another referendum on independence.
But that may not be enough to placate those who have found their angry voice over the past week.
Once night fell Thursday, trash bins were in flames yet again.
"We have been in this independence movement for seven years already, and we are fed up," said a young man who was involved in the riots in Barcelona. The man, who had a bruise from what he said was a rubber bullet, refused to give his name because he feared retaliation from police.
"We're standing up now," he said.
Parra reported from Madrid. Associated Press journalist Renata Brito in Barcelona, Spain, contributed to this report.