Combine Shapes are new for PowerPoint 2011 and are a set of four tools that let you combine, unite, intersect, or subtract selected shapes in various ways, depending upon which shape overlaps the other. Unfortunately they are so well hidden that you may not even be aware that they exist! You won’t find these commands in any of the Ribbon tabs — nor will you be able to customize your toolbars to get these options. To view the Combine commands, you need to select two or more shapes. Then right-click (or Ctrl-click) the selection. In the resultant contextual menu, select the Grouping option to summon the sub-menu — you will find the four Combine Shapes commands here!
Learn about the Combine Shapes commands in PowerPoint 2011 for Mac.

