Extended ⍳ :  Tool of Thought Index   <<   >>

 

{(⍉↑⍺⍳¨⍺)⍳(⍉↑⍺⍳¨⍵)}

MatIota ← {(↓⍺)⍳↓⍵}
{(⍉↑⍺ MatIota¨⍺) MatIota (⍉↑⍺ MatIota¨⍵)}

{(⍉↑⍺{(↓⍺)⍳↓⍵}¨⍺) {(↓⍺)⍳↓⍵} (⍉↑⍺{(↓⍺)⍳↓⍵}¨⍵)}