The codenamed "Obsidian" User Interface (UI) for Tizen smartphone was developed by Intel and subsequently leaked in June 2013. Now there has emerged another video showing a more mature UI.
The Obsidian UI was different from the standard stock Tizen UI that has been seen on Developer devices (and little anywhere else) with its square elements and sharp angles. The newer version of the UI replaces the sharp corners with more rounded edges. The icons are now able to show additional notification counts as well as pop up information.
Here is a video of the old Obsidian UI: