Copyleft principle

1. Study the principle of copyleft and write an analysis about its three variants (strong, weak, none) with real-life examples.

The strong features of copyleft licence are the possibility to make software modifiable and leaving the source code open in order to let others improve it or make their own versions of it. The modified version should also be distributed with accessible source code and it should go with the copyleft clause. This enables the best possible solution for creating software, modify and improve it. For example the very same game we are developing, Wesnoth, is created by collaborative force, as is Mozilla Firefox and its extensions. These and other software solutions are in regular use by very many people nowadays.

In order to ensure that full copyleft is applied, it is necessary to determine in the copyleft that no copyright terms should not be applied and it can only be distributed under the same terms as the original version.
Different copyleft variants are strong, weak and non-copyleft. The weak copyleft derivatives might not have the same outcome as the original copyleft, or no copyleft at all. For example GNU Lesser General Public Licence and Mozilla Public Licence.
Full copyleft means that all parts of the work can be distributed only under the same licence as the original work. Partial copyleft allows only partial copyleft changes.

Copyleft is applied only when a person wants to redistribute the software, instead of restricting the distribution, it allows modification and further distribution.