Hello! Well wishes to you!
In this tutorial is seen varying arcs with more - or less - eccentricity. In practical trading terms, the eccentricity would be how much time the arc covers compared to how much price it covers.
An arc covering one days worth of time for a set amount of price would have more eccentricity - making it more oval shaped - than an arc...
Native chart:
The adjusted axis is gathered from the perpendicular to an axis of price, and the gann fann was gathered using the same slope as the previous descent axis. The arcs were gathered from the vector movement of the previous decline axis.
Suggested Reading:
Law of Vibration - Tony Plummer
Michael Jenkins - Geometry of Stock Market Profits, Chart...