uses graph, crt;
var
 px, py, ux, uy: integer;
 d, m, keskx, kesky: integer;
 nurk: real;
begin
 d:=detect; initgraph(d, m, '');
 nurk:=0; px:=15; py:=20;
 keskx:=100; kesky:=70;
 repeat
   ux:=round(px*cos(nurk)-py*sin(nurk));
   uy:=round(px*sin(nurk)+py*cos(nurk));
   cleardevice;
   putpixel(keskx+ux, kesky-uy, white);
   delay(15);
   nurk:=nurk+0.1;
 until keypressed;
 closegraph;
end.