I've seen some of his machines in Technology Museum in Berlin. The first iteration was mechanical done with cleverly cut out metal plates.
https://en.wikipedia.org/wiki/Z1_(computer)
Playlist showcasing the current restoration work: https://youtube.com/playlist?list=PLtpOUadaBh31n6Pdscwhwopmh...
https://en.wikipedia.org/wiki/Z1_(computer)
Playlist showcasing the current restoration work: https://youtube.com/playlist?list=PLtpOUadaBh31n6Pdscwhwopmh...