Reorder levels and chapters into a better sequence

levels/branches/branch-create

@@ -0,0 +1,35 @@
+title = Party Time
+cards = checkout commit-auto reset-hard branch
+
+[description]
+
+You were invited to two parties but they will happen at the same time! At party 1 your favorite band is playing and the other one is your best friend's birthday party.
+
+Where should you go? No worries - you are a time travel agent in training. You can go to both parties! To quickly switch between both events, check out the last commits and
+create branches with the `git branch [string]` command. Now you can easily switch between both branches by calling `git checkout [branch]`.
+
+[setup]
+
+echo "-Birthday present.
+-Concert ticket." > backpack
+git add .
+git commit -m "evening preparations"
+echo "-Birthday present." > backpack
+git add .
+git commit -m "go to the birthday"
+
+git checkout HEAD~1
+echo "-Concert ticket." > backpack
+git add .
+git commit -m "go to the concert"
+
+git checkout HEAD~1
+
+[win]
+
+NUM_BRANCHES="$(git show-ref --heads | wc -l)"
+test "$NUM_BRANCHES" -ge 3
+
+[congrats]
+
+Your friend is happy that you made it to the birthday party and you also got your concert ticket signed. Yay!

levels/branches/branch-remove

@@ -0,0 +1,47 @@
+title = Choose your own adventure
+cards = checkout commit-auto reset-hard branch-delete
+
+[description]
+
+Life is full of dangers, right? Even when walking to school, it seems like there's a lot of risks!
+
+This Monday is especially bad. You made it to school, but there's some timelines you definitely don't want to keep around.
+
+Find the bad branches and delete them. Keep the one that seems okay.
+
+[setup]
+
+echo You leave your house and start walking to school. > you
+git add .
+git commit -m "Good morning!"
+
+echo You walk on the right side of the street. >> you
+git commit -am "Right side"
+
+echo You jump over an manhole in the walkway, and arrive at school on time. >> you
+git commit -am "Jump"
+
+git checkout HEAD^ -b friend
+echo Suddenly, you fall down, splash into stinking water, and are eaten by an alligator. >> you
+git commit -am "A new friend"
+
+git checkout HEAD~2 -b music
+echo You walk on the left side of the street. >> you
+git commit -am "Left side"
+
+echo Because you\'re kind of late, you start running. Someone throws a piano out of their windows, and it smashes you. >> you
+git commit -am "Sounds nice"
+
+git checkout HEAD^ -b ice-cream
+echo You\'re not in a hurry, and walk slowly. You even get some ice cream on your way. You arrive at school too late, and your teacher is angry. >> you
+git commit -am "Yum"
+
+git checkout main
+
+[win]
+
+test "$(git branch | cut -c 3-)" = "$(echo -e ice-cream\\nmain)"
+
+[congrats]
+
+On second thought, maybe you even prefer the ice cream timeline to the main one? :)

levels/branches/branches

@@ -0,0 +1,103 @@
+title = Branching out
+cards = checkout commit-auto merge reset-hard
+
+[description]
+
+You can use these little blue labels to give names to different timelines! This makes it easier to remember what happened where.
+
+One of your colleagues messed up here - can you help reordering the branches correctly using the "reset" card?
+
+When you do commits or merges while you're on a branch, the branch will grow with you. Try that while you eat that donut.
+
+Finally, merge all timelines together, in a way so that the "main" branch points to the result. That's base reality!
+
+---
+tipp1
+---
+tipp2
+---
+tipp3
+
+[setup]
+
+echo "A friendly old lady.
+Sells delicious baguettes." > mary
+
+echo "A rebellious teenager.
+Sells good coffee." > larry
+
+echo "A snail. Literally a snail.
+Sells donuts with an unspecified, slimy filling." > gary
+
+echo "You do not have a baguette.
+
+You do not have coffee.
+
+You do not have a donut." > you
+
+git add .
+git commit -m "The Beginning"
+
+git checkout -b coffee
+echo "You have a baguette.
+
+You do not have coffee.
+
+You do not have a donut." > you
+git add .
+git commit -m "You buy a baguette"
+
+echo "You ate a baguette.
+
+You do not have coffee.
+
+You do not have a donut." > you
+git add .
+git commit -m "You eat the baguette"
+
+git checkout -b baguette main
+echo "You do not have a baguette.
+
+You have coffee.
+
+You do not have a donut." > you
+git add .
+git commit -m "You buy some coffee"
+
+echo "You do not have a baguette.
+
+You drank coffee.
+
+You do not have a donut." > you
+git add .
+git commit -m "You drink the coffee"
+
+git checkout -b donut main
+echo "You do not have a baguette.
+
+You do not have coffee.
+
+You have a donut." > you
+git add .
+git commit -m "You buy a donut"
+
+git checkout --detach main
+
+[win]
+
+# Did you eat a baguette on the main branch?
+git show main:you | grep "You ate.*baguette"
+
+# Did you drink a coffee on the main branch?
+git show main:you | grep "You drank.*coffee"
+
+# Did you eat a donut on the main branch?
+git show main:you | grep "You ate.*donut"
+
+[actions]
+
+test "$(git rev-parse HEAD^)" = "$(git rev-parse donut)" && hint "Ooops, your branch ref is still on the old commit."
+
+[congrats]
+
+Nice! It's often convenient to stay on branches most of the time!

levels/branches/branching

@@ -0,0 +1,53 @@
+title = Parallelism
+cards = checkout commit-auto
+
+[description]
+
+Did you know that creating parallel timelines is perfectly legal and safe? It's true!
+
+Can you find out when things went wrong in this zoo, and create a parallel universe where everyone is happy?
+
+[setup]
+
+mkdir cage
+echo "Looks very hungry." > cage/lion
+
+echo "A small child.
+It really loves cats!" > child
+git add .
+git commit -m "The beginning"
+
+echo "It's holding a lollipop." >> child
+git commit -am "The child buys something"
+
+mv child cage
+git add .
+git commit -m "The child climbs somewhere"
+
+git rm cage/child
+echo "Looks happy. :)" > cage/lion
+git add .
+git commit -m "Oh no"
+
+echo "It's sleeping." > cage/lion
+git add .
+git commit -m "Nap time!"
+
+git checkout --detach
+git branch -d main
+
+[win]
+
+# Is the child still there?
+git ls-tree --name-only -r HEAD | grep child
+
+# Is the lion not hungry?
+git show HEAD:cage/lion | grep -v "very hungry"
+
+[congrats]
+
+Whew, good job! This seems like a *much* better outcome.
+
+Feel free to add more parallel timelines, or make them longer.
+
+If you're ready, our next mission is already waiting...