> mandel:= proc (x, y, i_max)

  local xc, yc, xOld, yOld, xNew, yNew, i;
  xc:= x:   yc:= y:
  xNew:= 0: yNew:= 0:
  i:= 0:
  while ((xNew*xNew < 4) and (i < i_max)) do
    xOld:= xNew:  yOld:= yNew:
    xNew:= xOld*xOld - yOld*yOld + xc:
    yNew:= 2*xOld*yOld + yc:
    i:= i + 1;
  od:
  if i = i_max then 1 else 0 fi;
end:

> depth:= 1000;

xAnf:= -2;
xEnd:= 0.5;
yAnf:= -1.25;
yEnd:= 1.25;

xStep:= (xEnd - xAnf)/depth;
yStep:= (yEnd - yAnf)/depth;

> M:= {}:

anz:= 0:
Startzeit:= time ():
x:= xAnf - xStep:
for i to depth do
  x:= x + xStep:
  y:= yAnf - yStep:
  for j to depth do
    y:= y + yStep:
    if (mandel(x, y, 800) = 1) then
       anz:= anz + 1:
       P||anz:= [x, y]:
       M:= M union {P||anz}:
    fi:
  od:
od:
Laufzeit:= time () - Startzeit:

> pointplot(M, view = [-2..0.5, -1.25..1.25],

  symbol = POINT,
  color = black,
  axes = boxed
  axesfont = [COURIER, 12],
  scaling = CONSTRAINED);