Infinities
small and big
Mathematics should then be studied, that it puts the mind right.
Mikhail Lomonosov
Mathematics gives the most reliable rules: the one who follows them is not in danger for the deception of the senses.
Leonard Euler
Once, as a child, I swam with a mask near the shore, looked at the pebbles at the bottom, the flickering of sunlight in clear sea water. Swimming further, I watched the bottom darken: more depth - less light. Once I swam up to a rock that stuck out vertically from the water as a flat wall. And then, at a smooth rock, sinking into the depths, I saw infinity. The light gradually faded along the sheer wall. I hung over a bottomless abyss. There was absolute darkness below. It got scary. With all my might, I swam to the shore.