PHILADELPHIA (AP) — As thousands crowd the streets and parks of Philadelphia in heated protest outside the Democratic National Convention, Andrew Purchin swapped a picket sign for an easel. Purchin, an artist and psychotherapist from Santa Cruz, set up shop in Philadelphia this week, inviting convention-goers to find alternative outlets for political expression. Purchin first asked people to pick up a paintbrush at the Republican National Convention, where his water and oil paints served as an oasis amid the heat and chaos on the streets of Cleveland. Purchin, 54, has painted since he was 16, but his passion for politics was stirred decades later when, in 2009, Barack Obama became America's first black president.