diff --git a/chapter-3-composite-types/01_arrays.go b/chapter-3-composite-types/01_arrays.go
index 51406f6..900ceb3 100644
--- a/chapter-3-composite-types/01_arrays.go
+++ b/chapter-3-composite-types/01_arrays.go
@@ -1,6 +1,8 @@
 // array literals are their own types
 // [3]int is a different type to [4]int
 
+// dont use arrays unless you know the exact length ahead of time
+
 package main
 
 import "fmt"
@@ -17,4 +19,15 @@ func main() {
 
 	// can leave the size off if initialising an array
 	var z = [...]int{1, 2, 3}
+
+	// comparison
+	fmt.Println(z == x)
+
+	// an array of length 2, of type array length 3 (2x3 matrix)
+	var m [2][3]int
+	fmt.Println(m)
+
+	// accessing elements
+	fmt.Println(x[0])
+	fmt.Println(x[len(x)-1])
 }
diff --git a/chapter-3-composite-types/02_slices.go b/chapter-3-composite-types/02_slices.go
new file mode 100644
index 0000000..374a26c
--- /dev/null
+++ b/chapter-3-composite-types/02_slices.go
@@ -0,0 +1,16 @@
+// the length is not part of the type for a slice
+
+// slices use the same syntax as arrays for accessing/assigning
+
+package main
+
+import "fmt"
+
+func main() {
+	// []int makes a slice, [...]int makes an array
+	x := []int{10, 20, 30}
+	fmt.Println(x)
+
+	x = []int{1, 5: 4, 6, 10: 20, 11}
+	fmt.Println(x)
+}