uniform half4 colorGreen, colorRed;

half4 main(float2 coords) {
    float val = 0.0;
    // complex cond (mod uses sqrt(a) twice), simple next
    for (float a = 12.0; a > mod(sqrt(a), 0.5); a -= 1.0) {
        val += a;
    }
    // simple cond, complex next (mod uses 1.0-sqrt(a) twice)
    for (float a = 0.0; a < 20.0; a = a + mod(1.0 - sqrt(a), 3.0) + 1.0) {
        val += a;
    }
    // both complex
    for (float a = 12.0; a > mod(sqrt(a), 0.5); a = a - mod(1.0 - sqrt(a), 3.0) - 1.0) {
        val += a;
    }
    return val > 0.0 ? colorGreen : colorRed;
}