Propagation and other shiet

[mec328]

Description

TODO

Change type

• New feature

Test type(s)

Type N/A if a type of test is not relevant

• [N/A] Unit tests
• Numerical (Monte Carlo, e.g.) tests
• Simulation tests

Checklist

This list must be completed before merge.

• All parties affected by this change are reviewers/watchers. (in a world where i have other contributors :P)
• Any new features include relevant unit tests, numerical tests, or simulation tests.
• All tests pass.
• The code follows the repo's style guidelines and structure.
• The code is well organized, commented, and has been reduced as much as possible to simple, testable pieces.