⊤ Encode r←[x]⊤y

If x is not provided, it defaults to the scalar 2.

If x is non-scalar, operates on vectors of x and scalars of y, the following recursive procedure is performed:

• let b be ⊇x and bs be ¯1↓x
• let rem be b=0⍰y⍠b|y and div be b=0⍰0⍠⌊y÷b
• r is rem⍪⍨bs⊤div

If x is scalar, operates on vectors of y, x must have magnitude greater than 1 and the following recursive procedure is performed:

• if y=0, then r is ⟨⟩
• let rem be x|y and div be ⌊y÷x
• let rem1 be x|div and div1 be ⌊div÷x
• if rem=rem1 and div=div1 then r is y
• otherwise r is rem⍪⍨x⊤div

with the difference that encoding 0 returns ⟨0⟩ instead of ⟨⟩.