# • Mar 23, 2026 • 4 min read • Erik Sagen
The Serendipity of Noticing
What we don't notice until we open our eyes.
Last week I was researching delta time; the concept of change over time, and stumbled across the delta symbol itself. You know it: the triangle-shaped mark, Δ. Uppercase delta. It represents difference or variation. I'd seen it scattered throughout my life before, but I'd never really seen it.
Then something happened.