uses
	crt,
	go32;

const
	columns = 80;
	rows = 25;
	screensize = rows*columns*2;

	text = '! Hello world !';

var
	textofs : Longint;
	save_screen : array[0..screensize-1] of byte;
    curx, cury : Integer;

begin
	randomize;
	dosmemget($B800, 0, save_screen, screensize);
	curx := wherex; cury := wherey;
	gotoxy(1, 1); Write(text);
	textofs := screensize + length(text)*2;
	dosmemmove($B800, 0, $B800, textofs, length(text)*2);
	dosmemfillchar($B800, 0, screensize, #0);
	while (not keypressed) do begin
		dosmemfillchar($B800, textofs + random(length(text))*2 + 1,
			1, char(random(255)));
		dosmemmove($B800, textofs, $B800,
			random(columns)*2+random(rows)*columns*2,
			length(text)*2);
		delay(1);
	end;
	readkey;
	readkey;
	dosmemput($B800, 0, save_screen, screensize);
	gotoxy(curx, cury);
end.