Extract terminal in its own scene, add a few proper levels with a description

levels/02-tree/description

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+Blobs just have some content and an ID. It would be convenient to be able to give names to a blob, right?
+
+The second type of Git object is called a "tree" - a tree points a bunch of blobs, and gives each of them a name!
+
+How can we build our own trees? Introducing: the index!
+
+The index is like a "work in progress" version of a tree, where we can add and remove blobs. When we're happy with what we have built, we can make it into a real tree object!
+
+We can use
+
+    $ git update-index --add <file>
+
+to make the file's content into a blob, and to add that blob to the index using the file's name.
+
+When we're happy with out index, we can convert it into a tree using
+
+    $ git write-tree
+
+That command will output the ID of the newly crated tree.
+
+Build a tree containing just the 'noises' file, which we conveniently placed in your current directory! :)