Ошибка в коде, индекс находился вне границ массива - PascalABC.NET

Program laba5;
 
uses GraphABC, events;
 
const
 windowsizex=1000;
 windowsizey=660;
 cornerx=1;
 cornery=1;
 
 statusheight=160;
 field=10;
 font=10;
 noteplacey=30;
 resultplacey=85;
 placey=140;
 placex=940;
 statuscolor=clteal;
 markcolor=clpurple;
 
 rectanglex1=225;
 rectangley1=285;
 rectanglex2=775;
 rectangley2=545;
 
 colornumber=5;
 sizenumber=3;
 shapenumber=4;
 
 smalllength=20;
 middlelength=40;
 biglength=60;
 
 arrayborder=100;
 
type
 figure=record
         x,y,color,shape,size:integer;
        end;
var
 mas:array[1..arrayborder] of figure;
 i,number,borderx,bordery:integer;
 result:string;
 
 procedure main;
  begin
   rectangle(cornerx,cornery,windowsizex,statusheight);
   setbrushcolor(statuscolor);
   fillrect(cornerx,cornery,windowsizex,statusheight);
   setfontsize(font);
   setfontcolor(clblack);
   setfontstyle(fsBold);
   textout(field,field,'Добро пожаловать в программу вычисления количества красных фигур внутри прямоугольника!');
   textout(field,noteplacey,'Нажмите "Начать" для запуска программы или "Выход" для завершения работы.');
   textout(field,resultplacey,'Фигур внутри прямоугольника: ');
   textout(field,placey,'Начать');
   textout(placex,placey,'Выход');
   setbrushstyle(bsclear);
   setpencolor(clblack);
   rectangle(rectanglex1,rectangley1,rectanglex2,rectangley2);
  end;
  
  procedure pen;
 
  begin
   case mas[i].color of
         0: setpencolor(clred);
         1: setpencolor(clgreen);
         2: setpencolor(clblue);
         3: setpencolor(clyellow);
         4: setpencolor(clgray);
        end;
  end;
  
 procedure drawcross(x1,y1,size1,pen1:integer);
  begin
   pen;
   line(x1-size1,y1,x1+size1,y1);
   line(x1,y1-size1,x1,y1+size1);
  end;
 
 procedure drawskewcross(x1,y1,size1,pen1:integer);
  var
  n:integer;
  begin
   n:=trunc(size1*0.7);
   pen;
   line(x1-n,y1-n,x1+n,y1+n);
   line(x1-n,y1+n,x1+n,y1-n);
  end;
  
 procedure drawcircle(x1,y1,size1,pen1:integer);
  begin
   pen;
   setbrushstyle(bsclear);
   circle(x1,y1,size1);
  end;
  
 procedure drawstar(x1,y1,size1,pen1:integer);
  var
  n:integer;
 begin
   n:=trunc(size1*0.7);
   pen;
   line(x1-n,y1-n,x1+n,y1+n);
   line(x1-n,y1+n,x1+n,y1-n);
   line(x1-size1,y1,x1+size1,y1);
   line(x1,y1-size1,x1,y1+size1);
 end;
 
 procedure press(mousex,mousey,mmousey:integer);
 var i:integer;
  begin
   if (mousex>=placex)and(mousex<=placex+45) and (mousey>=placey)and(mousey<=placey+font+5) then
    begin
     setbrushcolor(markcolor);
     textout(placex,placey,'Выход');
     closewindow;
    end
   else if (mousex>=field)and(mousex<=field+55) and (mousey>=placey)and(mousey<=placey+font+5) then
    begin
     ClearWindow;
     main;
     setbrushcolor(markcolor);
     textout(field,placey,'Начать');
     number:=0;
     for i := 1 to arrayborder do
      with mas[i] do
       begin
        size:=random(sizenumber);
        case size of
         0: size:=smalllength;
         1: size:=middlelength;
         2: size:=biglength;
        end;
        borderx:=windowsizex-2*size;
        x:=random(borderx)+size;
        bordery:=windowsizey-2*size-statusheight;
        y:=random(bordery)+statusheight+size;
        color:=random(colornumber);
        shape:=random(shapenumber);
       end;
     for i:=1 to arrayborder do
      begin
       with mas[i] do
        begin
         case shape of
          0: drawcross(x,y,size,color);
          1: drawskewcross(x,y,size,color);
          2: drawcircle(x,y,size,color);
          3: drawstar(x,y,size,color);
         end;
        if (pencolor=clred)and(x-size>rectanglex1)and(x+size<rectanglex2) and (y-size>rectangley1)and(y+size<rectangley2) then number:=number+1;
       end;
     str(number,result);
     setbrushcolor(statuscolor);
     textout(field+235,resultplacey,result);
  end;
  end;
  end;
begin
 setwindowsize(windowsizex,windowsizey);
 ClearWindow;
 centerwindow;
 main;
 onmousedown:=press;
end.

 procedure pen;
 
  begin
   case mas[i].color of
         0: setpencolor(clred);
         1: setpencolor(clgreen);
         2: setpencolor(clblue);
         3: setpencolor(clyellow);
         4: setpencolor(clgray);
        end;
  end;