Guiding Ships with Moire Patterns

The author built a working moire pattern navigation device inspired by a historical maritime guidance system, which creates a visual beam that helps guide ships through channels by displaying a narrow line of light when viewed from the correct angle. While the moire system functions intuitively and requires minimal calibration, the author argues that a simpler three-light alignment system is more practical for real-world harbor navigation, as it alerts pilots only when they're actually in danger rather than whenever they deviate slightly from an ideal course.