Two flat square mirrors joined at the edge in a right angle, standing upright. Just that.

In an ordinary mirror, if you point with your left hand as shown here, the right hand of the
reflected image does the pointing. Standing before an ordinary mirror, if you point to the left,
the reflected person in the mirror also points in the same direction relative to you as you face 
the mirror. In the inverted mirror, when I point with my left hand, the figure in the mirror also
 points with ITS left hand, non-inverted. However, that reflection of myself points off to ITS left,
 which is off to MY right as I sit before the mirror. 

As I took this picture, I was pointing with my left hand to MY left, and holding the camera with my 
right hand, as shown. 

The non-inverting sorcerer's mirror does not turn your right hand into your left, and vice versa.  
Most people are so careless looking into a mirror that they do not even notice that when they use 
the right hand, say to brush their hair, the reflected person uses its left hand. Try brushing your 
hair while looking in the sorcerer's mirror and you immediately get the difference. You cannot at 
first coordinate the hand motion with the image you see. The sorcerer's mirror breaks the habitual 
chiral lock of the first attention. 

"Non-inverting" means that the reflected person in the mirror uses the right and left hands in a 
way identical to the person standing before the mirror. The ordinary mirror turns your right hand 
into the left hand of the reflected person, and vice versa. In the ordinary mirror, the tatoo of a 
black swan on my right are appears on my left arm, etc.