Mirroring entities
You can create a mirror image of an entity. You mirror the entity about a mirror line, which you define by specifying two points in a drawing. You can delete or retain the original entities.
To mirror entities
1 Do one of the following to choose Mirror ():
On the ribbon, choose Edit > Offset (in Modify).
On the menu, choose Modify > Mirror.
On the Modify toolbar, click the Mirror tool.
Type mirror and then press Enter.
2 Select the entity, and then press Enter.
3 Specify the first point of the mirror line.
4 Specify the second point of the mirror line.
5 In the prompt box, choose one of the following:
Yes, Delete Entities deletes the original entities.
No, Keep Entities retains the original entities.