In the process of developing the Marble Machine X & MMXt, Wintergatan is collaborating with Volunteering Collaborators. This text will clarify the nature of these Collaborations and applies to all collaborations where no other written agreement exists.
1.1. Wintergatan is the Creator and inventor of the marble machine: https://www.youtube.com/watch?v=IvUU8joBb1Q. Wintergatan is now developing the Marble Machine further.
The Collaborator wishes to assist the Development on the terms set out below.
2.1. The Collaborator agrees that service provided within the Collaboration is carried out for free.
2.2. The Collaborator shall have the right to be credited by good practice when the Results are publicly disclosed. 
2.3. In certain cases, Wintergatan shall bear some of the costs and expenses that may arise in connection with the Collaboration. Any reimbursement for purchases regarding the Collaboration have to be explicitly approved in writing by joanna@wintergatan.net before executed. 
2.4. The Collaborator agrees that all Collaboration results shall be the property of Wintergatan, with the exception and clarification in paragraphs 2.5 and 2.6
2.5 The Collaborator maintains full ownership over their own contributed ideas, copyrights, patents, trade secrets, and other intellectual property. They are free to patent or commercialize their ideas, regardless of whether they have been applied in the Marble Machine project. 
2.6 When a Collaborator brings an idea or design, copyright protected or not, to the project, the Collaborator will issue Wintergatan a free, worldwide license to use and commercialize the ideas in conjunction with the Marble Machine in perpetuity. The License Covers all activities performed on Planet Earth as well as on Planet Mars. 
2.7 Wintergatan has the full right to use or sell the Marble Machine in any way Wintergatan wishes. No legal objection should be made from the Collaborator, who voluntarily and freely donated their ideas to the project.
If the above sounds fair to you, let's collaborate, if not, we wish you good luck with anything you are doing!
Thank you for being a part of the Marble Machine X
Martin & Wintergatan