I assume you mean the old, pre-4.7 design[1]? Interestingly, Oxygen itself ditched those for a less glossy design that had always reminded me of the (now old!) OSX icons. Not really sure what to make of that.

[1] http://icons.iconarchive.com/icons/oxygen-icons.org/oxygen/2...

[2] http://4.bp.blogspot.com/-Wemowf_4MrE/TjsIa4wrZeI/AAAAAAAAA1...