So Twitter is testing a new redesign — wait, is that Facebook?

A square profile picture on the left hand side, coupled with a long horizontal cover image and a row of tabs. No, it’s not your Facebook page — but it could be Twitter’s new look.

The social media giant seems to be testing a redesigned profile page with a small subset of users — among them, Mashable‘s assistant features editor Matt Petronzio. The updated page does away with Twitter’s traditional top-down vertical timeline of tweets, replacing them with a Pinterest-like grid of cards, featuring tweets and expanded images.

It’s the second design tweak Twitter has rolled out in recent weeks — the team updated its website in January, changing the icons, colours and fonts to make its web presence consistent with its various mobile apps. This version still uses those elements, but adds in a more visual element, with the content cards highlighting images and making sure users have more than just a few text-heavy tweets to look at when they visit another’s profile.

Although Twitter has allowed users to upload a prominent header photo since September 2012, they have previously been shown behind a user’s profile photo and bio. The changes will require users to switch out their current 1252 x 626 pixel image to a longer, thinner 150 x 1500 pixel one.

The changes come at an interesting time in Twitter’s history, as the site moves from an ambitious startup to a publicly listed company. Twitter’s first quarterly results since its IPO show that it is still running at a loss, with its slowing user growth becoming a concern for early investors.

It’s a progression Twitter has anticipated though — in its filing with the Securities and Exchange Commission, it warned that a drop in user growth and engagement could see its revenues take a hit, as it generates most of its money from advertising. By making these latest design changes, Twitter may be hoping to keep users from growing bored and keep them engaged with its platform by adopting previously successful features and layouts. But we’ll have to wait and see if it noticed a positive reaction to the profile tweaks and rolls out the changes on a mass scale once its testing period is over.