7 works, 7 spheres. The number seven can be found in many areas of life. Seven wonders of the world, seven parts of the world, seven heavenly bodies and seven days of the week.
It is said to have psycho-logical and mythological properties in many parts of the world - it unites spirit, soul and body on the one hand and the four elements symbolically on the other in one plane - an enveloping shell that encloses a centred core. The spheres refer to a delimited space that is individually defined. A self-identified atmosphere - everything is reality and illusion at the same time.