A reporter asks a billionaire how he earned his wealth

Here's the billionaire's response:

A long time ago, I had absolutely nothing but a penny. So I took that penny and bought a pencil from the corner store. Sold it to my classmate for two cents. Then I bought two pencils, sold them for four cents. Two became four, four became eight, then sixteen, then thirty-two... until I had $20.48.

That's when my father had a massive heart attack, and I inherited $47 billion.