func checkMandelbrot(c complex128, res chan int) {
z := settings.z0
for i := 0; i < settings.repeat; i++ {
z = cmath.Pow(z, settings.n) + c
if 2.0 < cmath.Abs(cmath.Pow(z, 2)) {
res <- i + 1
return
}
}
res <- -1
}
func mandelbrot(c complex128) int {
z := c
for i := 0; i < 127; i++ {
if cmath.Abs(z) > 2 {
return i
}
z = z*z + c
}
return 127
}