Lens-system configurations of the lensing event KMT-2021-BLG-2609 for the five local solutions. The top panel provides a wide-angle perspective, showcasing the caustic and the position of the planet. The planet is marked by a small filled dot. Each of the lower panels presents a close-up view around the caustic. In these panels, the red figure indicates the caustic, while the arrowed line represents the source trajectory. The grey curves surrounding the caustic represent equi-magnification contours. Additionally, the blue circle positioned on the source trajectory represents the source whose size is adjusted to match that of the caustic.