(require 'maxima)
/*           HERE BEGINS MAXIMA SESSION            */

(%i1) fract(xmin,xmax,ymin,ymax,nr,nc,c):=
        block([maxcolor:1,maxiter:50,bound:100,
                zn,zn1,m,dx,dy,k,numer:true],
        m: zeromatrix(nr,nc),
        dx:(xmax-xmin)/nc,
        dy:(ymax-ymin)/nr,
        for i:1 thru nr do
                for j:1 thru nc do(
                        zn:(xmin+(j-1)*dx) +%i*(ymin+i*dy),
                        k:1,
                        while k<=maxiter and abs(zn)<bound do(
                                zn1: expand(c*zn*(1-zn)),
                                zn:zn1,
                                k:k+1),
                        m[i,j]:if k>maxiter then 1 else 0),

        /* removes previous file fractal.pnm, if any */
        system("rm fractal.pnm"),

        /* saving the image in pnm format */
        with_stdout("fractal.pnm",
                print("P2"),
                print(nr, nc),
                print(maxcolor),
                for i:1 thru nr do
                        for j:1 thru nc do
                                print(m[i,j])),

        /* call ImageMagick and paint this sort of insect */
        system("display fractal.pnm") )$

(%i2) showtime:true$

Evaluation took 0.00 seconds (0.00 elapsed) using 32 bytes.
(%i3) fract(-0.5,1.5,-1,1,300,300,1.64+0.96*%i);

Evaluation took 419.03 seconds (425.08 elapsed) using 8326622.844 KB.
(%o3)                       #<process 3049 :EXITED>
(%i4) /* format conversion */
      system("convert fractal.pnm fractal.png")$

Evaluation took 0.02 seconds (0.08 elapsed) using 12.422 KB.
(%i5)

/*           HERE ENDS MAXIMA SESSION            */
--