In a poor neighborhood on the outskirts of Sao Paulo, the sounds of a fiddle merge with the buzz of an electric saw as apprentice craftsmen build Brazilian folk instruments - often using wood found in city dumps.
In Sao Miguel Paulista, in the eastern part of this enormous Brazilian city, David Rocha, 20, shows off one of his most recent creations: a "rabeca," a violin-like instrument popular in Brazilian culture.
"I learned to play with sheet music in church," he told AFP.
Rocha is a member of the Tide Setubal Foundation, a community organization which is seeking to rescue the popular culture of a region of modest homes and widespread emigration in the impoverished Brazilian northeast.
To make money, he sells some of the instruments, which are made of wood and scraps collected from the banks of the polluted Tiete river.
With patience and skill, Rocha gently places his hands on the strings of his latest instrument, a "cavaquinho" - a small, four-stringed guitar - freshly painted, and made of three native woods: imbuia, known as Brazilian walnut, jacaranda, a blue-flowering tree, and an evergreen tree known as araucaria.
Rocha's rabeca was made with araucaria, imbuia and pau-brasil, a type of Brazilian timber that he took from an old bed.
One of Rocha's guitars was made from a box of imported Norway cod he found one day at the central market in Sao Paolo.
"I find the wood on a vacant lot or on the banks of the Tiete. When it is waterlogged, I take it back to the workshop and let it dry," said Rocha, who has lost count of how many instruments he has made.
Surrounded by handsaws and hammers, Renato Soares, 21, and Caique Aron, 18, are finishing their second "alfaia", a drum popular in Brazil's northeast which resembles the drums used in 19th-century military marching bands. Strips of rope wrapped around the drum's body can be tightened or loosened for tuning.
"It's for the five-year-old brother of a friend of mine," says Soares. "Since he plays the flute, I promised him I would make him an alfaia, since it makes more noise," said Soares, laughing.
Back at the workshop, the cupboards are full of percussion instruments, both large and small, some with the leather already tanned and cured, others with the original skin. They will be used for music lessons for about 60 children who come to the Foundation for lessons.
Along with his percussion-making skills, Soares is one of the drum instructors.
"I like building them," he says, noting how he makes the bright purple and yellow diamonds that decorate the sides of the alfaia with ink, glue and sawdust.
After creating his latest cavaquinho, Rocha must test it out - and an impromptu samba duo with Soares on the alfaia is the best way to do that.