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What about Python?
What about ROOT?
Marlin uses AIDA -> RAIDA -> Root (But there already exists RAIDA, which is "remote AIDA", so we appear to be running out of acronyms.)
What about FLUKA?
What about Geant3
...
?
What about AliRoot?
4th concept is using it.
What about Gismo, LCDRoot, LCDG4?
These are all deprecated simulation packages.
What about EGCS and GHEISHA?
These FORTRAN packages formed the basis for some Geant4 code, so they live on (kind of).