bar/** seems to work differently than .gitignore

For files like
<pre><code>
.
├ foo
│  └ bar
│     └ some_file.txt
└ bar
   └ other_file.txt
</pre></code>

When I ignore:

    bar/**

Both `foo/bar/some_file.txt` and `bar/other_file.txt` will be ignored.

But for `.gitignore`, only `bar/other_file.txt` will be ignored.