Following each flail, a clear graphic representation of your strokepath along with several key stats will display on your device: the critical putter-face angle at impact and tempo, among others.
To check if it actually works as advertised, we set up a a video camera to film the stroke from overhead, then compared the plotted result with the strokepath displayed on a smartphone, as shown in the video below.
The included app's well-designed interface shows an animation of your putts and displays a curve indicating the path of your stroke, which can be overlaid against that of a previous, model putt you've chosen.