Some details of the Wash Sale rule I don’t quite understand

According to Investopedia:

The Wash-Sale Rule states that, if an investment is sold at a loss and then repurchased within 30 days, the initial loss cannot be claimed for tax purposes. In order to comply with the Wash-Sale Rule, investors must therefore wait at least 31 days before repurchasing the same investment.

There are some scenarios where I'm not quite clear on.

Scenario 1:

• January 1st sold 100 shares of Disney for a loss.
• January 15th purchased 1 share of Disney.

Does this trigger the rule? Does the 1 share ruin the whole 100 shares?

Scenario 2:

• January 1st bought 1 share of Apple for $100
• January 7th sold 1 share of Apple for $90
• January 14th bought 1 share of Apple for $80

Does this trigger the rule even though you're buying at an even lower price than the original purchase?

Scenario 3:

Does this trigger the rule?

Scenario 4:

Does this trigger the rule?