diff --git a/crystal/README.md b/crystal/README.md
index ef8ca1786..0ec4a1eaf 100644
--- a/crystal/README.md
+++ b/crystal/README.md
@@ -34,6 +34,13 @@ filter or grep => reject   (use the names other languages use for the same conce
 
 What is "flag?"  ? I saw it in the source code of Kemal, but I don't see it defined anywhere.
 
+GitHub Actions configurators: https://crystal-lang.github.io/install-crystal/configurator.html
+
+Yak Shaving
+
+https://forum.crystal-lang.org/ has around 500 users.
+https://gitter.im/crystal-lang/crystal Gitter 1960 people
+
 
 ### SQLite
 
@@ -41,3 +48,6 @@ Lack of documentation
 last_id  last_insert_id  How can one know?
 
 puts __FILE__
+
+
+
diff --git a/crystal/examples/assign.cr b/crystal/examples/assign.cr
new file mode 100644
index 000000000..1a42e89bd
--- /dev/null
+++ b/crystal/examples/assign.cr
@@ -0,0 +1,3 @@
+a = b = 42
+puts a # 42
+puts b # 42
diff --git a/crystal/examples/constants.cr b/crystal/examples/constants.cr
new file mode 100644
index 000000000..a9161941f
--- /dev/null
+++ b/crystal/examples/constants.cr
@@ -0,0 +1,4 @@
+PI = 3.14
+
+puts PI
+PI = 3.145 # Error: already initialized constant PI
diff --git a/crystal/examples/multiple_assignments.cr b/crystal/examples/multiple_assignments.cr
new file mode 100644
index 000000000..ccee865c7
--- /dev/null
+++ b/crystal/examples/multiple_assignments.cr
@@ -0,0 +1,8 @@
+a, b = 2, 3
+puts a  # 2
+puts b  # 3
+
+
+a, b = b, a
+puts a  # 3
+puts b  # 2
diff --git a/crystal/other.md b/crystal/other.md
index 2923043dc..7f8110531 100644
--- a/crystal/other.md
+++ b/crystal/other.md
@@ -224,3 +224,39 @@ shards install
 
 ![](examples/docspec/src/app.cr)
 
+## require
+{id: require}
+
+{aside}
+require - imports are global. This makes it hard to see in a file where some objects might come from
+as they might have been required by some other file.
+
+Similarly requiring a bunch of files in a directory is easy to do, but might make it a bit harder for
+someone without an IDE to find the source of each object.
+{/aside}
+
+```
+require "./directory/file"  # relative path to the cr file
+require "./directory/*"     # all the cr files in the directory
+require "./directory/**"    # all the cr files in the directory - recursively
+require "some_name"         # Find it somewhere (standard library, src directory)
+```
+
+* You can put the `require` statements anywhere but you might want to be consistent in your porject.
+* Make sure you don't have circular requires.
+
+## Constants
+{id: constants}
+
+* Variable names that start with upper-case letter are constants
+
+![](examples/constants.cr)
+
+## Multiple assignments
+{id: multiple-assignments}
+
+![](examples/multiple_assignments.cr)
+
+![](examples/assign.cr)
+
+
diff --git a/crystal/spec/todo_spec.cr b/crystal/spec/todo_spec.cr
new file mode 100644
index 000000000..8cfc9a933
--- /dev/null
+++ b/crystal/spec/todo_spec.cr
@@ -0,0 +1,18 @@
+def add(x, y)
+    return x*y
+end
+
+
+describe "test cases" do
+  it "good" do
+    add(2, 2).should eq 4
+  end
+
+  pending "another test case when the bug is fixed"
+  it "add" do
+    add(2, 3).should eq 5
+  end
+  it "add" do
+    add(2, 4).should eq 6
+  end
+end
diff --git a/crystal/testing.md b/crystal/testing.md
index d8c3ec7ad..73a5cb908 100644
--- a/crystal/testing.md
+++ b/crystal/testing.md
@@ -21,6 +21,8 @@ crystal spec .
 
 ![](spec/demo_spec.cr)
 
+![](spec/todo_spec.cr)
+
 ```
 crystal spec
 ```