const a=10; var x,y,z,w,k,dx,dy; begin k:=1; display(400); dx:=20; dy:=20; x:=200; y:=100; while 1=1 do begin color(k); k:=k+1; if k=5 then k:=1; w:=-30; while w<60 do begin z:=-30; while z<60 do begin if z*z + w*w < 1000 then draw(x+z,y+w); z:=z+1; end; w:=w+1; end; x:=x+dx; y:=y+dy; if x=400 then dx:=-dx; if x=0 then dx:=-dx; if y=400 then dy:=-dy; if y=0 then dy:=-dy; end; end.