“Whereas adults speak,” the artist Francis Alÿs explains, “children play to assimilate the realities they encounter.” Since 1999, following this logic, Alÿs has documented children playing in public places. He’s filmed hopscotch and catch games in Belgium, Hong Kong, Mexico, and the Democratic Republic of the Congo. For the presentation at Wiels, several new films are on view, including children’s games that Alÿs filmed recently in Ukraine. In between bird calls, hide and seek, and shrieks, the children shed light on different realities. —Elena Clavarino