diff --git a/chapter_4/exercises.md b/chapter_4/exercises.md new file mode 100644 index 0000000..e69de29 diff --git a/chapter_4/notes.md b/chapter_4/notes.md new file mode 100644 index 0000000..e69de29 diff --git a/chapter_4/test_yourself.md b/chapter_4/test_yourself.md new file mode 100644 index 0000000..e69de29