diff --git a/README.md b/README.md
index a985e82df422f56066af2ea273ace806faca7c08..009af3f4d82296db5ccdb0a67daeb0111bd50d8c 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 > [!IMPORTANT]
 > There are more involved libraries out there providing better granularity
 > and functionality. This library is intended for ease of use first and
-> foremost. It is not a replacement for those libraries.
+> foremost. It is not a replacement for those libraries. Use at your own risk.
 
 ## Features
 
@@ -220,3 +220,7 @@
 ```bash
 make test
 ```
+
+## Acknowledgments
+
+- https://github.com/tsoding/nob.h
\ No newline at end of file
diff --git a/nonstd.h b/nonstd.h
index f4f62926284900688890e17c52905d0286d54d27..3e39380e7edf59c3af8515e177b80e42d0310e52 100644
--- a/nonstd.h
+++ b/nonstd.h
@@ -60,7 +60,18 @@ #define MIN(a, b) ((a) < (b) ? (a) : (b))
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 #define CLAMP(x, lo, hi) (MIN((hi), MAX((lo), (x))))
 
-#define UNUSED(x) (void)(x)
+// From https://github.com/tsoding/nob.h/blob/e2c9a46f01d052ab740140e74453665dc3334832/nob.h#L205-L206.
+#define UNUSED(value) (void)(value)
+#define TODO(message)                                                      \
+	do {                                                                   \
+		fprintf(stderr, "%s:%d: TODO: %s\n", __FILE__, __LINE__, message); \
+		abort();                                                           \
+	} while (0)
+#define UNREACHABLE(message)                                                      \
+	do {                                                                          \
+		fprintf(stderr, "%s:%d: UNREACHABLE: %s\n", __FILE__, __LINE__, message); \
+		abort();                                                                  \
+	} while (0)
 
 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
 #define STATIC_ASSERT(expr, msg) _Static_assert((expr), msg)