Within an hour after the Paris attacks, an artist’s heartfelt symbol of peace became a worldwide sign of support for France. The illustration is powerful in its simplicity: A peace symbol (originally by Gerald Holtom) with the Eiffel tower, rendered in bold, black strokes against a white background. Jean Jullien created the image, “Peace for Paris,” and posted it on Twitter and Instagram. Jean Jullien has developed a remarkable ability to synthesize.