Fold, 2018

void mainImage( out vec4 O, in vec2 f ){ vec2 uv = f/iResolution.xy -.5 + vec2(-.07,.27); float a = atan(uv.y, uv.x)*.37, e = mod(2.0 * a + iTime * .7, 2.); O = vec4(sin(a * e)); }