void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    vec2 uv = fragCoord.xy / iResolution.xy;

    float bass = 0.5 + 0.5 * sin(iTime * 3.0);
    bass *= 0.7 + 0.3 * sin(iTime * 0.7);

    vec3 col = vec3(
        uv.x * bass * 3.0,
        uv.y,
        bass
    );

    col += 0.15 * sin(iTime + uv.xyx * 8.0);

    fragColor = vec4(col, 1.0);
}