Current Twitter logo
The first Twitter logo was designed by Simon Oxley , a British graphic designer who posted in iStock, a photography site in stock. And at that point, Oxley didn't know what Twitter was.
Twitter 2007
But Twitter eventually gave up the logo in 2009 because the company was not allowed to use images from iStock for its official logo.
In 2012, Twitter decided to put the blue bird symbol on happiness to make the official logo of Twitter and use it until today. The logo now has some changes in the shape of the wing feathers as well as the position of the bird's mouth.