diff --git a/lec13/th3.c b/lec13/th3.c
new file mode 100644
index 0000000000000000000000000000000000000000..2ec2f10c40ecea94ec85c69890000c31bcbeaca7
--- /dev/null
+++ b/lec13/th3.c
@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+int bbb = 0; 
+
+void fn_s()
+{
+    static int a = 0; 
+    printf("== %d %d ==\n",a++, bbb++);
+}
+
+
+void *run (void *arg)
+{
+    printf("Hello world of POSXI threads.%d\n", (int) (0) );
+    for (int i = 0; i < 100; i++)
+	{
+		sleep(1); 
+		fn_s(); 
+	}
+    return 0;
+
+}
+
+int main()
+{
+	int result1;
+	run((void *) 0); 
+	sleep(10);
+
+	run((void *) 0); 
+	printf("Thread return %d at the end\n", result1);
+}
+