program szakasz;
uses graph, crt;
const f=240;
      szin=lightgray;
var gd,gm,x,y,p:integer;
begin
  detectgraph(gd,gm);
  initgraph(gd, gm, 'c:\tp70\bgi');
  repeat
    p:=random(4);
    case p of
     0: begin
        x:=round(x/2)+f;
        y:=round(y/2)+f;
        end;
     1: begin
        x:=round(x/2);
        y:=round(y/2)+f;
        end;
     2: begin
        x:=round(x/2)+f;
        y:=round(y/2);
        end;
     3: begin
        x:=round(x/2);
        y:=round(y/2);
        end;
    end;
    putpixel(x,y,szin);
  until keypressed;
  closegraph
end.