{} {⍺} {⍵} {⍺⍵}
⍴⍴⍵ ≢⍴⍵ {0} {0}¨ +/∧\⍵ +/∧\' '=⍵ ∧\' '=⍵
0=≡⍵ 1=≡⍵ 1=≡,⍵
0=⍴⍵ 0∊⍴⍵ ~0∊⍴⍵ x,←⍵ x⍪←⍵
0=⍴⍴⍵ ,/⍵ ⍪/⍵ x↓⍨←⍺ {⍵[⍋⍵ ]} {⍵[⍒⍵ ]}
0=⊃⍴⍵ 0≠⊃⍴⍵ {⍵[⍋⍵;]} {⍵[⍒⍵;]}
⊣/⍵ ⊢/⍵ ⊣⌿⍵ ⊢⌿⍵ {(⊂⍒⍵)⌷⍵} {(⊂⍋⍵)⌷⍵}
⍺/⍳⍵ ⍺/⍳⍴⍵ ⊃⌽⍺ ⊃⌽,⍵
~∘' '¨↓⍵
⍺⊃¨⊂⍵ ⎕AV⍳⍵ {(+/∨\' '≠⌽⍵)↑¨↓⍵}
⊃∘⍴¨⍵ *○⍵ {(∨\' '≠⍵)/⍵} {(↓⍺)⍳↓⍵}
↓⍉↑⍵ ⌊0.5+⍵ {(+/∧\' '=⍵)↓⍵}