diff --git a/crystal/README.md b/crystal/README.md
index c02ebe86b..1e81d8afd 100644
--- a/crystal/README.md
+++ b/crystal/README.md
@@ -20,7 +20,10 @@
 
 ## Ideas for slides
 
-I run 
+The need to recompile the whole thing before I run it and the fact that compilation is slow makes life of a (web) developer hard.
+The Jinja Template system of Johannes that does not need to be compiled makes at least the HTML development much faster.
+
+I run
 crystal example.cr
 I get
 Showing last frame. Use --error-trace for full trace.
diff --git a/crystal/arrays.md b/crystal/arrays.md
index 5a974ae12..49d02f1e0 100644
--- a/crystal/arrays.md
+++ b/crystal/arrays.md
@@ -118,3 +118,16 @@
 {id: arrays-join}
 
 ![](examples/arrays/join.cr)
+
+## Remove nil elements
+{id: remove-nil-elements}
+{i: compact}
+
+![](examples/arrays/remove_nils.cr)
+
+## Create Array with nil
+{id: array-with-nil}
+{i: 0_i64}
+
+![](examples/arrays/array_with_nil.cr)
+
diff --git a/crystal/examples/arrays/array_with_nil.cr b/crystal/examples/arrays/array_with_nil.cr
new file mode 100644
index 000000000..3e95dcd26
--- /dev/null
+++ b/crystal/examples/arrays/array_with_nil.cr
@@ -0,0 +1,6 @@
+n = 5
+nums = (0_i64.as(Int64 | Nil)..n).to_a
+puts typeof(nums) # Array(Int64 | Nil)
+
+other = [nil] + (1..n).to_a
+puts typeof(other) # Array(Int32 | Nil)
diff --git a/crystal/examples/arrays/remove_nils.cr b/crystal/examples/arrays/remove_nils.cr
new file mode 100644
index 000000000..19dc41781
--- /dev/null
+++ b/crystal/examples/arrays/remove_nils.cr
@@ -0,0 +1,7 @@
+numbers = [nil, 2, 3, nil, nil, 7, nil]
+puts numbers
+puts numbers.compact
+puts numbers
+
+puts numbers.compact!
+puts numbers
diff --git a/crystal/examples/int64_zero.cr b/crystal/examples/int64_zero.cr
new file mode 100644
index 000000000..5c1c84201
--- /dev/null
+++ b/crystal/examples/int64_zero.cr
@@ -0,0 +1,4 @@
+zero = 0_i64
+
+p! zero
+p! typeof(zero)
diff --git a/crystal/examples/range/to_a.cr b/crystal/examples/range/to_a.cr
new file mode 100644
index 000000000..5328e456c
--- /dev/null
+++ b/crystal/examples/range/to_a.cr
@@ -0,0 +1,3 @@
+numbers = (2..7).to_a
+p! typeof(numbers)
+p! numbers
diff --git a/crystal/examples/range/to_a.out b/crystal/examples/range/to_a.out
new file mode 100644
index 000000000..d1c275b2f
--- /dev/null
+++ b/crystal/examples/range/to_a.out
@@ -0,0 +1,2 @@
+typeof(numbers) # => Array(Int32)
+numbers # => [2, 3, 4, 5, 6, 7]
diff --git a/crystal/other.md b/crystal/other.md
index 5087e2ad1..8d0d4a784 100644
--- a/crystal/other.md
+++ b/crystal/other.md
@@ -284,3 +284,8 @@ require "some_name"         # Find it somewhere (standard library, src directory
 ![](examples/case_when_on_type.cr)
 
 
+## Int64 Zero
+{id: int64-zero}
+
+![](examples/int64_zero.cr)
+
diff --git a/crystal/range.md b/crystal/range.md
index ed2d78660..4e926b2ae 100644
--- a/crystal/range.md
+++ b/crystal/range.md
@@ -47,3 +47,10 @@
 ![](examples/range/step.cr)
 ![](examples/range/step.out)
 
+## Range to Array
+{id: range-to-array}
+{i: to_a}
+
+![](examples/range/to_a.cr)
+![](examples/range/to_a.out)
+