In-and-Out Chord Diagram 1: Build a chord system via construction

This example demonstrates an “in-and-out chord diagram” geometry: it constructs two related chord structures (inner and outer) within a single coordinated figure, highlighting how intersection patterns and symmetry arise from the same underlying setup. Key mathematical ideas include chord geometry, relationships created by intersecting lines, and the way rotation produces corresponding inner/outer configurations while preserving structural links. Construction-wise, it relies on GeoGebra commands Intersect to locate key crossing points; Polygon to create polygonal scaffolding; Line and OrthogonalLine to define baseline lines and perpendiculars; and Rotate to replicate parts of the configuration into the outer/inner positions. Suitable for middle school through early undergraduate learners, especially for lessons on transformation geometry, geometric construction, and intersection-based reasoning.