It was the middle of the night, and Pia Guerrera, a 46-year-old Vancouver-based artist, felt helpless. News of the deadly mass shooting at Marjory Stoneman Douglas High School in Parkland, Fla. had just unfolded over Valentine’s Day, and she couldn’t bring herself to go to sleep. So she began to draw. “It’s not often that … Continue reading This artist’s cartoon about school shootings is striking a chord with thous…