This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Reflection at fixed and free string ends single pulse. en Reflection of single pulse on string at fixed end and at free end The red line is used for constructing an image wave Superposition with pulse of opposite sign keeps the endpoint fixed own Pieter Kuiper px Created with Mathematica Animations of vibrations and waves Reflection