To post an animated GIF to this site:

1. Upload it as media.
2. When inserting it into your post you must select the full sized option as shown.

Otherwise, wordpress makes a copy of it and does not actually post the original file.

To create an animated GIF from your sketch there are two options.

1. Run your sketch and then create a GIF from it using liceCap. You can download licecap here.
2. Use the animated GIF library. For library documentation go here: http://extrapixel.github.io/gif-animation/

Here’s the library implemented in a sketch.