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Square Image Of (⊏)
⊏ 𝕩: First Cell
First major cell of 𝕩.
⊏ ⟨1, 2, 3⟩
a ← 3‿3 ⥊ ↕9
⊏ a
𝕨 ⊏ 𝕩: Select
Select the major cells of 𝕩 at the indices in 𝕨.
2‿0 ⊏ ⟨1, 2, 3⟩
b ← 3‿3 ⥊ ↕9
2‿0 ⊏ b
