(* generates an image of the mandelbrot set; takes a while to run *)

iter[x_, y_, lim_] := Block[{c, z, ct},
		c = x + I y;
		z = c;
		ct = 0;
		While[(Abs[z] < 2.0) && (ct<lim), ++ct;
			z = z*z + c;
		];
	Return[ct];
	]
DensityPlot[-iter[x,y,50], {x,-2.0,1.0},{y,-1.5,1.5},
	PlotPoints->120, Mesh -> False]