but you might take Stig's concern to heart. Reactors might, as he says not allow a mirror command to work if you don't want to leave the original objects in the drawing. If you don't have a strong understanding of how things happen in autocad, like what it takes to perform a mirror, you surely don't want to start messing with reactors. Also, if you don't have a sound understanding of lisp, you don't want to start off with reactors. If, on the other hand, you do have a sound understanding of these things, then have fun.