Twitter got a lot of attention for updating its bird logo this week, but one thing went largely unmentioned: Twitter doesn't have a text logo anymore — the company retired it a while ago to go full bird. This was a simple branding decision, they say. Or was it????

As pointed out by reader Iain K. MacLeod, Twitter's old logos, and Facebook's current ones, share something in common, as revealed by a simple rotate-and-flip: