had like a lot of mining out there, it have, sometimes, like 80 freight cars gonna be pulled to gunnison or maybe pulled to pueblo or somewhere like that. and boy, it used to be tough at nighttime because at nighttime, these cars would all clank together like the freight car would come up and they wanna get them all clanked together. and it turns out that the coupling between the cars was loose. so instead of them coming up and, boom, one great big clank, there'll be clank and then clank, clank, clank, clank, clank, clank, clank, 78, 79, 80, oh, hey, pull, 80 clanks. and, whew, now, i can go to sleep. but then what happened is they just connected together. now, they're gonna pull this way. and what happens is clank, clank, clank, clank and that's it 78, 79, 80. and i used to think to myself, "why don't they take those couplings "and tighten them up so they don't all clank? why do they do that?" who--i know why, i know why, i know why--begins with f. physics. physics. physics. yey, all right. it's because of the physics. let me ask you, guys, a question. you wanna put-- you wanna set into