​I am a 71 year old engineer and inventor. Amongst other I have made a mechanical building kit for fun. All the building modules are made for 3D-printing, and You can download them for free from the download store 'MyMiniFactory' : https://www.myminifactory.com/users/He-Ideas. On my homepage https://he-ideas.weebly.com you can have an overview of the kit. I have added the section 'Ideas and stuff ' where you can have a look at some of my other crazy ideas. I also added a 'NASA Challenges' -section, where you can see my contributios to some of their many challenges.