and here's a sandy beach. there's sand and water down here. this is a helicopter view. and down here is a person drowning. drowning in the water, so the sharks are coming and something like that. now, you're the lifeguard-type up here. and you want to get from here to here in the least time, okay? so, you might say, well, i'll take a straight line path. good idea, or not good idea? begin with n, g. not. not good idea. hc. has the person-- oh, you don't-- well--let me ask you a question, how fast can you go across the sand compared to how fast can you swim? fast enough. how can you move faster, across the sand or swimming? how many of you say, "honey, i'm not so good in the land, but man, you should see me in the water." [laughs] come on, come on, most of us could go faster across the land, yeah? so it might be that you would say, "hey, what i'll do, is i wanna go the shortest distance to the water." so i'll run over here, and then run straight down. do you think that's the shortest time? if you run very, very, very fast and swim very, very, very slow, case to be made, y