M Pastinha set up his first capoeira school in Campo da Pólvora
[..] when [M Pastinha] was discharged from the army, being 20 years old, he opened his first school in the room that served as the headoffice of a group of cyclists, located in the belvedere of Campo da Pólvora, in Salvador.
Reis, 1997
Was it here where M Pastinha got the idea of building a fence for the spectators of his capoeira demonstrations in the end of 1940s? See those here. An observation: the two squares are situated close to one another.
We also know that M Pastinha liked football alot and that the football uniforms (see Esporte Clube Ypiranga, founded in 1906, winning the Bahian Championships first time in 1917), that he adopted also indicate a link to Campo da Pólvora.