diff --git a/all.sh b/all.sh
new file mode 100755
index 0000000..1e84c74
--- /dev/null
+++ b/all.sh
@@ -0,0 +1,9 @@
+#!/bin/bash
+set -eo pipefail
+
+script_dir="$(dirname "$0")"
+
+find "$script_dir" -type d -name 'day*' | while read dirname; do
+    echo "$dirname"
+    make -C "$dirname" "$@"
+done