No two signatures by one person are exactly the same in style, so the new technique involves making a 3D model of the pressure applied when a person writes.
The model translates the writing into an image showing dips and furrows of the sample so that anomalies can be detected.
Conventionally, handwriting has been analysed by forensic experts in 2D, looking at the sequence of pen strokes in handwriting, like a signature.
But this is not entirely accurate, because the exact sequence of strokes is not always clear and can vary.
Suggested by Rosemary, who as I recall used to refuse to sign those digital credit-card receipt machines. I used to be very pious about refusing to do that, but nowadays when I shop I’m usually with kids, and am eager to avoid any delay at the cash register.