The walkers and runners Those who get up early on Sunday to exercise on the banks of the Besòs River are surprised when they see, near the Badalona neighborhood of Artigues, a group of boys and girls running up and down with a PVC stick between their legs and various types of balls in their hands that they throw at their friends, and try to act like a circus, strategically arranged on the grass that exists between the water and the bike path. "Some ask us what we play, others indiscreetly film us and some cyclists who call us 'Harry Potter!'" laughs Brais Costoya, one of the regulars at the Sunday sessions of the Catalan quadball team, a discipline that was born in 2005 from sport and the inspiration of quiddit. It has been practiced in Barcelona for years.