Case 0

Clone the repository
Create a commit
Create a branch
Switch branches

Case 1

Merge branch branch2 in branch1
Merge branch branch4 in branch3
Merge branch branch3 in branch1
Merge branch branch1 in master

Case 2

Amend the last commit and fix the typo in the commit log.

Case 3

Group commits that looks alike

Case 4

Split the commit logs into multiple meaningful commit logs.

Case 5

Split a specific commit into multiple commits

Case 6

Find which commit introduced an issue.