diff --git a/src/std/box-recursive.md b/src/std/box-recursive.md
index 75e616b1..157c7e3b 100644
--- a/src/std/box-recursive.md
+++ b/src/std/box-recursive.md
@@ -30,3 +30,12 @@ fn main() {
 `- - - - - - - - - - - - -'     '- - - - - - - - - - - - - - - - - - - - - - - -'
 ```
 
+<details>
+    
+If the `Box` was not used here and we attempted to embed a `List` directly into the `List`,
+the compiler would not compute a fixed size of the struct in memory, it would look infinite.
+    
+`Box` solves this problem as it has the same size as a regular pointer and just points at the next
+element of the `List` in the heap.    
+    
+</details>