Drag and drop an image onto the white background or click here for a default image. Then right-click somewhere into the image or move your mouse with the left mouse button held down.
Should work with recent desktop versions of Chrome or Firefox, and probably also with other browsers.
This is a little experiment I wrote for fun: a simple cloth simulation using handcrafted asm.js code and homemade WebGL shaders. Techniques used (in case you're interested in the math behind this) include Verlet integration, relaxation, and Taylor approximation. No external libraries were employed. See the source code for details.

Copyright (c) 2016, Prof. Dr. Edmund Weitz.