9. Untangle both the element and solver class hierarchy
10. Move all the private element data into global vectors; this could allow to implement 1) without writing a dump/restore method for each element and/or without resorting to CRIU
## Medium projects
1. recover existing soft restart. See also [this GSoC project idea](https://gitlab.polimi.it/Pub/mbdyn/wikis/Google-Summer-of-Code/GSoC-Project-Ideas#cascaded-analysis)