program FernIFS;
uses GRAPH, CRT;

const NUMIT = 128000;
var  a, b, c, d, e, f : array [1..4] of real;

(*********************************)
procedure Load_Arrays;
 begin
  a[1]:=0; b[1]:=0;
  c[1]:=0; d[1]:= 0.16;
  e[1]:=0; f[1]:=0; {p[1]:=0.01;}
  a[2]:=0.85; b[2]:=0.04;
  c[2]:=-0.04; d[2]:=0.85;
  e[2]:=0; f[2]:=1.6; {p[2]:=0.85;}
  a[3]:=0.20; b[3]:=-0.26;
  c[3]:=0.23; d[3]:=0.22;
  e[3]:=0; f[3]:=1.6; {p[3]:=0.07;  }
  a[4]:=-0.15; b[4]:=0.28;
  c[4]:=0.26; d[4]:=0.24;
  e[4]:=0; f[4]:=0.44; {p[4]:=0.07; }
 end;
(*********************************)
 procedure prepit;
 var driver, mode : integer;
 begin
   driver:= DETECT;
   initgraph(driver, mode, '');
 end;
(*********************************)
 procedure chaos;
 var currit, rndnum : longint;
     x, y, plotx, ploty : real;
     pick : integer;

 begin
   x:=0; y:=0;
   randomize;
   for currit:= 1 to NUMIT do
   begin
     pick := random(101) - 84;
     if (pick <= 0) then rndnum:=2
      else if (pick<=7) then rndnum:=3
      else if (pick<=15) then rndnum:=4
      else rndnum:=1;
     plotx:= ((a[rndnum]*x + b[rndnum]*y + e[rndnum]));
     ploty:= ((c[rndnum]*x + d[rndnum]*y + f[rndnum]));
     x:= plotx;
     y:= ploty;
    putpixel(round(plotx*100)+320, round(ploty*100), BLUE);
   end;
 end;
(*********************************)
 begin
   prepit;
   Load_Arrays;
   Chaos;
   sound(100); sound(1000);
   delay(45);
   nosound;
   readln;
   CloseGraph;
 end.