This is better known as Continuum UI.
How to get this:
Click Start and in the Start Search box type in regedit. Press the Enter Key.
Click Yes to UAC.
Now locate the following registry location:
Right click on Launcher and create a new DWORD value named UseExperience
Double click on UseExperience and put the Value data to 1.Click OK.
Close the Registry Editor,
Now see the start menu. Right click on start menu tiles to get a number of options to resize eg.1×1,2×2,4×2,2×4,4×4.