What's the difference between Paper.js and Interact.js?

Paper.Js <a href="https://github.com/paperjs/paper.js" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;paperjs&#x2F;paper.js</a><p>Interact.Js <a href="https://github.com/taye/interact.js" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;taye&#x2F;interact.js</a>