Brittany sat under an alcove in Harvard Square, sign in hand and a cup of loose change in front of her. She sets up there nearly every day, she says, with the same sign but with a different Dunkin’ Donuts cup. Her blue-dyed tips peek out of her yellow, owl-printed bandana. Kal stands next to her. He’s a soft-spoken shaggy-blonde-haired boy and when he speaks, Brittany smiles and nods, reassuring him. As her smile widens, her wrinkles deepen.