diff --git a/threads.js b/threads.js
index 1aeacb5..92243b0 100644
--- a/threads.js
+++ b/threads.js
@@ -6,3 +6,14 @@ const start = Date.now();
 crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
   console.log('1:', Date.now() - start);
 });
+
+crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
+  console.log('2:', Date.now() - start);
+});
+crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
+  console.log('3:', Date.now() - start);
+});
+
+crypto.pbkdf2('a', 'b', 100000, 512, 'sha512', () => {
+  console.log('4:', Date.now() - start);
+});