the state department must then give your son or daughter an immigrant visa number, even if he or she is already in the united states. this should really talk to your imagination, lungs full of fresh air in the great outdoors versus clumps of dust sniffed directly from your sofa. nothing has to be working just there. our scientists and engineers, who make wonderful inventions, do too. but we have to take these impossibility results with a grain of salt: they only say things about the worst case graphs. do you want the invisible tracker? 