Merge mode
            
            Using the First, Middle,
               and Second merge modes, the center
               of the stamp face is made to match with the center of the face the
               hole is made on.
            
            The Project
                  Merge modes make the hole exactly where the stamp face resides.
               These modes do not center the hole but align the hole flat with
               the plane face. They also do not rotate the face to match the center
               as with the First, Middle,
               and Second merge modes.
            
            - First
- 
                  The face selected second
                        is transformed to make the centers match. The first selected face
                        does not get transformed.
                      
- Middle
- 
                  Both the first and the
                        second faces are transformed to make their centers match.
                      
- Second
- 
                  The face selected first
                        is transformed to make the centers match. The second selected face
                        does not get transformed.
                      
- Project First
- 
                  The second selected face
                        is projected onto the first and the centers do not match. The face
                        is not rotated, unlike the First merge mode where the face is rotated
                        to match the center.
                      
- Project Middle
- 
                  Both faces are projected
                        onto a plane lying between them; their centers do not necessarily match.
                      
- Project Second
- 
                  The first selected face
                        is projected onto the second selected face and the centers do not match.
                      
- None
- 
                  The stamp face projects
                        directly onto the face plane you select. This is the default.