Hi
We have the toroidal core made of glass.
On the all surface of this core is put upon the layers
.a/ The one of these layers it is the metal
b/ The second of these layers it is dielectric
The metal layer is put on the dielectric leyer
successive continously- in cycles.

It is so likely ,when snake swollows itself and
it grows.
This way it is possible to made specific transformer on more than 15
millions volts
Sincerelly E.W.