in_elastic

in_elastic(t: float) -> float

Elastic ease in - like pulling back a rubber band before release.

Creates an oscillating motion that starts with small movements in the opposite direction, building tension before accelerating toward the target. The elastic effect creates a spring-like anticipation that makes the final movement feel more impactful. Mathematical form: Uses -2^(10(t-1)) * sin((t-1) * 2π/3) for oscillating decay Use cases: - UI elements that need playful, bouncy character - Attention-grabbing animations for buttons or notifications - Game mechanics that simulate elastic or spring-loaded objects - Anticipation effects before major actions - Cartoon-style animations that need exaggerated character - Loading animations that suggest building energy Like drawing back a slingshot: small backward movements building tension, then rapid acceleration toward the target with overshooting oscillation.