monad ⊂ , ⍪ ⌹ ⍉ f⌿ f⍀ ⊖ {⍵[⍋⍵]} {⍵[⍒⍵]} {⍵[⍋⍵;]} {⍵[⍒⍵;]} dyad {⍺⍵} , ⍪ ⌹ ⍉ x/y x⌿y ≡ ≢ ⍳ ⌷ ↑ ↓ f
where f is a primitive scalar dyadic function