"Mandelbrot set (undocumented function)
#hide
PlotStep = 1','PlotWidth = 600','PlotHeight = PlotWidth
#show
$Map{Mandelbrot(x; y) @ x = -2 : 0.5 & y = -1.25 : 1.25}
$Map{Mandelbrot(x; y) @ x = -0.59 : -0.58 & y = 0.55 : 0.56}