... if they're reallycourageous, they'll say that it would be astall as a refrigerator. But the real answeris that the height of the stack wouldapproximate the distance to the sun. And ... giveyou a large piece of paper, and I ask youto fold it over once, and then take thatfolded paper and fold it over again, andthen again, and again, until you haverefolded the original paper 50 ... that little causes can have big effects; and three, thatchange happens not gradually but at onedramatic moment — are the same threeprinciples that define how measles movesthrough a grade-school...