diff --git a/src/vec/vec.h b/src/vec/vec.h
index b463320..c989d8e 100644
--- a/src/vec/vec.h
+++ b/src/vec/vec.h
@@ -5,6 +5,8 @@
 #include "typed_list.h"
 #include <math.h>
 
+#define V3_ELEM_COUNT 3
+
 typedef struct i64x2 V2i;
 struct i64x2 {
   i64 x;
@@ -32,7 +34,7 @@ struct f32x2 {
 typedef struct f32x3 V3f;
 struct f32x3 {
   union {
-    f32 elements[3];
+    f32 elements[V3_ELEM_COUNT];
     struct {
       union {
         f32 x;