Marble/MarblesSecrets

Marble's Secrets

A good introduction to get started is:

Marble's Secrets Part I: Behind the Scenes of Marble...

https://blogs.kde.org/2008/02/09/marbles-secrets-part-i-behind-scenes-marble

Marble's Secrets Part II - Walking In The Shoes Of Slartibartfast ...

https://blogs.kde.org/2008/02/10/marbles-secrets-part-ii-walking-shoes-slartibartfast

Marble's Secrets Part III: The Earth in a Download

https://blogs.kde.org/2008/02/12/marbles-secrets-part-iii-earth-download

Marble's Secrets Part IV: Run Marble, Run!

https://blogs.kde.org/2008/11/20/marbles-secrets-iv-run-marble-run