Improve the understanding of a simple examples (C/AC)

[lorismichel]

• programming a function to produce understandable plots for a specific example
• understanding the shifts between missing and non-missing
• selecting a few examples where the expected behaviour. Predictability vs stability is known and observed by us.

[lorismichel]

@lorismichel writing clean code, easy to handle for simulated data @spohnm causal example & @JeffNaef anti-causal