This is a photo of the top of my replica
This is a view of the bottom. Note the scribe
point in the center of the central component and at the central
component is not as thick as the two fences.
When the two fences of the device are held
firmly against the sides of a workpiece, the scribe point on the
bottom is on dead center. It can be used to mark a point or
dragged to scribe a line.
In this photo you VP an see that the central
beam of the device is exactly in the middle of the board.
I decorated the sides with ebonized wood inlays.
Note that the central component is thinner than the sides to
allow them to serve as fences.