diff --git a/rustbyexample/custom_types/custom_types_constants.rs b/rustbyexample/custom_types/custom_types_constants.rs
new file mode 100644
index 0000000..85e6426
--- /dev/null
+++ b/rustbyexample/custom_types/custom_types_constants.rs
@@ -0,0 +1,16 @@
+static LANGUAGE: &str = "Rust";
+const THRESHOLD: i32 = 10;
+
+fn is_big(n: i32) -> bool {
+    n > THRESHOLD
+}
+
+fn main() {
+    let n = 16;
+
+    println!("This is {}", LANGUAGE);
+    println!("The threshold is {}", THRESHOLD);
+    println!("{} is {}", n, if is_big(n) { "big" } else { "small" });
+
+    // THRESHOLD = 5;
+}