diff --git a/examples/coroutines/simple_coroutines.v b/examples/coroutines/simple_coroutines.v
index c971056900..87a7016f80 100644
--- a/examples/coroutines/simple_coroutines.v
+++ b/examples/coroutines/simple_coroutines.v
@@ -8,7 +8,8 @@ import net.http
 
 fn foo(a int) {
 	for {
-		println('hello from foo() a=${a}')
+		// println('hello from foo()') // a=${a}')
+		C.printf(c'hello from foo() a=%d\n', a)
 		coroutines.sleep(1 * time.second)
 	}
 }
@@ -16,7 +17,8 @@ fn foo(a int) {
 fn foo2(a int) {
 	mut i := 0
 	for {
-		println('hello from foo2() a=${a}')
+		// println('hello from foo2()') // a=${a}')
+		C.printf(c'hello from foo2() a=%d\n', a)
 		coroutines.sleep(2 * time.second)
 		i++
 		// resp := http.get('https://vlang.io/utc_now') or { panic(err) }
@@ -30,7 +32,16 @@ fn foo2(a int) {
 
 fn foo3(a int) {
 	for {
-		println('hello from foo3() a=${a}')
+		// println('hello from foo3()') // a=${a}')
+		C.printf(c'hello from foo3() a=%d\n', a)
+		coroutines.sleep(3 * time.second)
+	}
+}
+
+fn foo4(a int) {
+	for {
+		// println('hello from foo4()') // a=${a}')
+		C.printf(c'hello from foo4() a=%d\n', a)
 		coroutines.sleep(3 * time.second)
 	}
 }
@@ -39,6 +50,7 @@ fn main() {
 	go foo(10)
 	go foo2(20)
 	go foo3(30)
+	go foo3(40)
 	$if is_coroutine ? {
 		println('IS COROUTINE=true')
 	} $else {