Two or more circles (or spheres) with different diameters but the same centre are concentric to each other.
Dear Visitor,
In addition to essential cookies, this website also uses non-essential cookies that serve the purpose of analyzing website traffic and personalizing your user experience. You can consent to the use of non-essential cookies (Google Analytics performance cookies and YouTube marketing cookies) as specified in Art. 6(1)(a) GDPR by moving the sliders below to green or by clicking the "Allow All Cookies" button. Further details can be found in our Privacy Policy (clause 5 et seq. cookies/analysis tools and plug-ins). You can also modify or withdraw your consent to the use of non-essential cookies at any time. We would be delighted if you could help us to improve our offering for you and other interested parties by giving your consent to us processing your data.
Essential cookies help make using a website possible by enabling basic functions such as page navigation and access to website forms. The website cannot function properly without these cookies.
Schützt vor Cross-Site-Request-Forgery Angriffen.
Speichert die aktuelle PHP-Session.
The use of performance cookies serves the purpose of improving the quality of our website and its content. Performance cookies help us understand how and by whom the website is used, allowing us to continuously optimize our services.
Performance cookies help website owners to understand how visitors interact with websites by collecting and reporting information anonymously. INFORMATION ABOUT THE TYPE OF DATA PROCESSED, THE PURPOSE OF THE DATA PROCESSING AND THE LOCATION WHERE THE DATA PROCESSING TAKES PLACE.
Marketing cookies are used to track visitors on websites. The purpose is to show ads that are relevant and appealing to each visitor and which are therefore more useful for publishers and third parties engaged in advertising.