What does Pause Button look like on Facebook?

On Facebook it is the design shipped in 16.0, shown above at full size. Older revisions are listed beneath it.

When did Facebook add Pause Button?

Facebook first drew Pause Button in 2.0, released February 20, 2017.

Meta Platforms, Inc. has shipped 12 versions of Pause Button. Each is dated, so you can see when the design changed.

Facebook 3.0

Facebook shipped a new design for Pause Button in 3.0, released December 2, 2018. The previous design is shown beside it.

✳ marks a release that redrew this emoji. The rest re-shipped the design unchanged.

What does Pause Button look like on Facebook?: On Facebook it is the design shipped in 16.0, shown above at full size. Older revisions are listed beneath it.
When did Facebook add Pause Button?: Facebook first drew Pause Button in 2.0, released February 20, 2017.
How many times has Facebook redrawn Pause Button?: Meta Platforms, Inc. has shipped 12 versions of Pause Button. Each is dated, so you can see when the design changed.