diff --git a/20201105/hello-1.c b/20201105/hello-1.c
new file mode 100644
index 0000000000000000000000000000000000000000..b19d80e9bd0bd7c5ed8f54b20c6a50d9166f03ac
--- /dev/null
+++ b/20201105/hello-1.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Hello, world!\n");
+  return 0;
+}
diff --git a/20201105/hello-2.c b/20201105/hello-2.c
new file mode 100644
index 0000000000000000000000000000000000000000..2dbbad99d102df43d00779483f789f03274353ca
--- /dev/null
+++ b/20201105/hello-2.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+  printf ("Hello, world!");
+  return 0;
+}
diff --git a/20201105/hello-3.c b/20201105/hello-3.c
new file mode 100644
index 0000000000000000000000000000000000000000..087b3ad2304138af63900056572aa62f69a353be
--- /dev/null
+++ b/20201105/hello-3.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+  printf (Hello, world!);
+  return 0;
+}
diff --git a/20201105/hello-4.c b/20201105/hello-4.c
new file mode 100644
index 0000000000000000000000000000000000000000..e27a989a53130e32f7861b61e00dd347b4730879
--- /dev/null
+++ b/20201105/hello-4.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+  "Hello, world!";
+  return 0;
+}