1 files changed, 2 insertions, 0 deletions

diff --git a/src/r0.bqn b/src/r0.bqn
index 8347f8bf..a7b7f4c4 100644
--- a/src/r0.bqn
+++ b/src/r0.bqn
@@ -30,6 +30,8 @@ Box ← {𝕩Fill⟨⟩⥊⟨𝕩⟩}
 ↑ ← {⊑⟜𝕩⌜↕𝕨}                       # LIMITED to number 𝕨 and list 𝕩
 ↓ ← {(𝕨⊸+⊑𝕩˙)⌜↕(≠𝕩)-𝕨}             # LIMITED to number 𝕨 and list 𝕩
 
+¨ ← { d←⥊𝕩⋄(≢𝕩)⥊(⊑⟜(⥊𝕨)𝔽⊑⟜d)⌜↕≠d } # LIMITED to equal-shape arrays
+
 _fold0←{
   l←≠𝕩 ⋄ F←𝔽
   r←𝕨 {l↩l-1⋄l⊑𝕩}⊘⊣ 𝕩