I was introduced to the ZYGR by Guy Cools in Warsaw at a Dramatrugy Workshop held there in 2014.

Each day we started with this 30 minute practice, which Guy explained to us, he'd developed over some time with a long term collaborator of his, Lin Snelling.
The movement itself consists of a relatively simple twist with the weight over one foot, looking to the back, and then swinging the arms to twist to the other side. The repetitive action of this movement, it's durational quality and holistic spiral make this a very adequate warm up. But more than than, when practiced in groups of people, (in Warsaw we were about 25 people) there exists a mass level of concentration and connectivity that can be very rewarding to take part in.
I came to call the practice Egyptian Trance, and now appreciate it's truly democratic and joyful qualities for starting the dance classes I teach.
Generally depending on the size of the room and the number of participants we arrange ourselves in a long line.

Two lines facing one another is also possible. There are only 3 simple rules I tell people, but have generally learnt to not say too much. 

1. Don't stop
2. Change it if you are in pain or bored
3. Try to stay with it

I remind people it's a listening exercise and tell them I will be responsible for the time.
And we begin.
We end mostly having disassembled the line and continue in the space, both individually and with partners, our own investigation into the form and rhythm of the movement.
After 30 minutes or less I try and take a full minute to stop and have the echo of the spiral slowly fade, allowing time to journey through, in memory at least, all it's mutations over the last 30 minutes
As with most duration based activities the simple process of 'staying with it' brings up interesting observations along the way and a sense of having travelled or journeyed through something.
Some observations I've made concern;

Leading/following, imposing my will, relinquishing it, corrupting the form: how and from where a movement changes, where my attention is directed, where my desire/interest resides, how disciplined can I be, tempo/rhythm and breath.

These became compelling enough interests for me that I began to practice alone, and the movement form the beginning of a performance I made in 2014 called, This is the Beginning.
It's is a very different practice when done alone, and without others can offer up challenges with concentration and discipline but as an investigation into repeatition and form provides lots of information.

Several of the other Swiss participants of the workshop in Warsaw came back to Switzerland and continued the practice in their own way, having like me formed such a postive connection to it. So ZGYR is alive and well here. Thanks to Guy Cools!