Kiki by Karthikye Mittal not only changes the default iOS 7 icons, it also allows you to change the shape of icons.
You can make the icons circular, diamond shaped, square or a peculiar shape which the developer calls squircle.
Kiki is a Winterboard theme, which is available in the BigBoss repo. After installing the tweak, you need to select Kiki from list of themes in the Winterboard app, along with the mask you want to apply to change the shape of the icons.
You can also apply the “Lettered Numpad theme” to replace the numbers of the passcode lock screen to letters.
Kiki with Square icon mask
Kiki with Squircle icon mask
Kiki with Circular icon mask
You can check out the video demo of the theme below:
Kiki is available for free on Cydia. Let me know what you think of the theme. Which one is your favorite theme for iOS 7 so far? Let me know in the comments.