While ← {𝕩{𝔽⍟𝔾∘𝔽_𝕣_𝔾∘𝔽⍟𝔾𝕩}𝕨@}´
d←>'0'-˜•FLines"day11"

Step ← {
  g←f←0× x←𝕩+1
  While {𝕤 ⋄ f ≢ f ∨ g ↩ (¬f) ∧ x>9 }‿{𝕤
    x +↩ (+´+˝)⎉2 3‿3↕{⌽⍉0∾˘𝕩}⍟4 g
    f ∨↩ g
  }
  x × ¬f∨g
}

•Out +´{+´⥊0=𝕩}¨ Step⍟(↕101) d
•Out 0 {∧´0=⥊𝕩 ? 𝕨 ; (𝕨+1) 𝕊 Step 𝕩} d