Variation of lensing caustics induced by planets. We illustrate two sets of caustics with planet-to-host mass ratios q = 2 × 10⁻³ (depicted in red) and q = 2 × 10⁻⁴ (depicted in blue). Within each set, a series of caustics demonstrates variations depending on the planetary separation s. The coordinates are centered at the position of the planet host and the lengths are scaled to the Einstein radius. The dotted circle centered at the origin represents the Einstein ring.