The pie menu items are filled in a specific order - first the left item then the right, the bottom item then the top, then the top diagonals and the bottom diagonals are filled last. If the numbers used for each position seems odd for this layout compare them to your numeric keypad.
The primary design of the pie menus is to place one menu item at each location. As we have found this can be abused to show many items at each location.
While items are added in order to specific locations, we can effectively 'skip' an item by having a label with no text taking the position we want blank, it will need to be followed by a call to
menu_pie() to make the next item to go to the next position otherwise it will be positioned with the label.
pie = pie.row()
pie = layout.menu_pie()