uses graphABC;
const length = 400;
const number_of_mod = 101;//у нас 4 стороны по 100 точек, значит квадрат у нас 100 на 100 и мод нужно ставить 101
var
x:array[1..length] of integer;
y:array[1..length] of integer;
OLDx:array[1..length] of integer;
OLDy:array[1..length] of integer;
newx,i:integer;

Procedure drawing;
var i:integer;
begin
for i:=1 to length do setpixel(x[i]+250,y[i]+250,clblack);
end;

begin
for i:=1 to 100 do begin   x[i]:=i;OLDx[i]:=i;y[i]:=1;oldy[i]:=1;end;
for i:=100 to 200 do begin x[i]:=i-100;OLDx[i]:=i-100;y[i]:=100;oldy[i]:=100;end;
for i:=200 to 300 do begin x[i]:=1;OLDx[i]:=1;y[i]:=i-200;oldy[i]:=i-200;end;
for i:=300 to 400 do begin x[i]:=100;OLDx[i]:=100;y[i]:=i-300;oldy[i]:=i-300;end;

drawing;
sleep(2000);
while true do
begin
for i:=1 to length do begin newx:=x[i];x[i]:=(x[i]+y[i]) mod number_of_mod;y[i]:=(newx+(2*y[i])) mod number_of_mod;end;
drawing;
sleep(100);
clearwindow;
if(y[1]=oldy[1]) and (x[1]=oldx[1]) then break;
end;
drawing;
writeln('Я ЗАКОНЧИЛ!!!!!!!!!!!!!');
end.