void mainImage( out vec4 fragColor, in vec2 fragCoord ) { vec2 uv = fragCoord.xy / iResolution.xy; vec2 v = uv - vec2(0.5); float k1 = 1.5; float k2 = 0.5; float r1 = length(v); float r2 = r1 * (1.0 + k1*(r1 * r1) + k2*(r1 * r1 * r1 * r1))…