Hi Michael @M_chael ,
When you Duplicate something with SHIFT+D, it puts the duplicated object in ‘Translation Mode’ and you don’t want to Move the duplicate, so you press the Escape key to cancel the movement (keeping the duplicate at the exact same pl;ace as the original). Then you ‘mirror’ it in the X, Y plane by Scaling it along the Z-Axis by -1 (that is: S, Z, -1). There is no Rotation performed in this process.
