Every enitity even objects like land and buildings are affected by the flows of energy within them.
Since ancient times civilizations have known this and have tried to utlise this. There are many theories of this. India has vaastu shastra (literally, scieicne of objects) and China has Feng Shui.
The interesting overlap between these sciences, espcially Vaastu Shastra, and Gann's methods is the importance of cardinality i.e. the directions, the varying strength directly proportional to the angles to the centre, and a sine wave of the strenght as the angles traverses aka vibration.
Not going indepth into these sciences, theories and its applications, but just a superficial skim of these concepts and how they apply to markets' vibrations.
So here's a brifiest introduction on Vaastu Shastra. Wikipedia page.
Vaastu shastra, in its essence (in my understanding), is studying the flow/movement, strength and ... of energy in an place. The place here can be building, city, temple or similar. The attempt here is to understand the underlying *significane* of these energies and their impact of people and their welfare. The attempt is to, therefore, manipulate these energies to manifest beneficial aspects. Such a manipulation is usually attempted by creating a flow, opening a channel, building barriers, protecting the energies etc.
From the perspective of Gann's methods, the important point is the the energies of various kinds are maximum at the cardinal points of directions - east, west, north and south. The secondary cardinals are equally important as they form the cusp of the primary directions. The layout of these points and the areas and channels are very similar to the methods of Gann Square of Nine. Below is a Vaastu Shastra and its usual depiction of the energies in form of Sri Vaastu Purusha (God of Vaastu).
Pic source: here
Below is an other image which Gann enthusiasts would find more familiar.
Pic source: here
Now, we will go a little deeper into how the Celtics and Vasstu Shastra can be used in understanding and deploying Gann.