When hit, a golf face acts as a trampoline or spring, which is one reason why the USGA refers to how hot a face can be as its "Spring Effect and Dynamic Properties" rule.
As a matter of physics, the highest trampoline effect always occurs in the middle of a trampoline or the middle of a golf face.
Major brands have used “variable thickness technology” for decades. This technology has the thickest part of the face in middle of the face, where as a matter of physics the highest trampoline effect exists to ensure that the face does not have a CT higher than 257.
Then the major brands thinned the thickest part of center to the outer edges of the face. Why? They do so in an effort to minimize as much as they can the reduced trampoline effect that continuously occurs further from the middle of the face. However, despite this thinning the CT values in the large areas adjacent to the center or the "sweet spot" of the face are much lower. This is why amateur golfers lose so much distance on hits outside the sweet spot.
Knuth Golf invented the novel idea of creating
three, largely independent "trampolines" or "3 sweet spots" in the face. We then invented the novel idea to significantly and immediately reduce the average thickness of the two areas adjacent to traditional sweet spot and then reduced the thicknesses in the remaining areas of the face for 2 additional sweet spots.
By doing so, we were able to create a much higher CT permitted by the 2016 USGA Rule to provide amateur golfers the significant opportunity that the USGA's 2016 CT provided for amateur golfers . . . namely amateur golfers can now for the first time obtain about the same distance whether they hit in the traditional sweet spot or the 2 new sweet spots on their approach shots for more greens in regulation for lower scores and more fun.