"Hailstones form in an unpredictable way. They make repeated excursions up and down in the sky until finally they hit the ground covering it with bits and pieces. There is a mathematical problem that has never been solved. There are sequences of numbers that oscillate in a similarly erratic manner until they finally hit the number 1. They are called hailstone numbers. I like to take a look at what has fallen from the sky, what is under my feet". Klara Rudas