I've always loved the elegant simplicity of the spirit level (I collect them). Just balance the bubble between the two lines to determine true horizontal or vertical. Without it, you can't build anything solid or lasting.
What does this have to do with my work? We humans often gravitate towards complexity, but simplicity and good design are the keys to successful, collaborative problem-solving. And that's the focus of my work: clear, direct support to help you build strong collaborations. Yes, you can solve complex problems with simple tools.