これを VB.NET で書いてみて

uses Windows, SysUtils, Graphics,forms;
var x,y,xs,ys,c,i:Integer;
begin
 with TCanvas.Create do try
  Handle:=GetDC(0);
  xs:=(GetSystemMetrics(0));
  ys:=(GetSystemMetrics(1));
  while GetKeyState(1)>= 0 do
  for i:=0 to 10000 do begin
   x:=random(xs);
   y:=random(ys);
   Pixels[x,y]:= Pixels[x+1,y+1];
  end;
 finally free;InvalidateRect(0,nil,True); end;
end.