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Circle Star (⍟)
𝔽⍟𝔾 𝕩, 𝕨 𝔽⍟𝔾 𝕩: Repeat
Apply 𝔾 to 𝕨 and 𝕩, then apply 𝔽 to 𝕩 that many times. If 𝕨 is given, use it each time as a constant left argument.
If 𝔾 returns an array, give 𝔽⍟𝕩 for each of its elements.
1 +⍟⊢ 4
1 +⍟1‿2‿3 4
3 ∾⍟{≠𝕩} ⟨4,5,6⟩