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+*View this file with results and syntax highlighting [here](https://mlochbaum.github.io/BQN/help/range_windows.html).*
+
+# Up Down Arrow (`↕`)
+    
+## `↕ 𝕩`: Range  
+    
+Return all indices to index into an array of shape `𝕩`, in the shape described by `𝕩`.
+    
+When given a single number, range from 0 to `𝕩-1`.
+    
+           ↕ 4
+
+           ↕ 4‿5
+
+    
+    
+## `𝕨 ↕ 𝕩`: Windows
+    
+Overlapping slices of `𝕩` which are of shape `𝕨`.
+    
+           5 ↕ "abcdefg"
+
+           a ← 3‿3⥊↕9
+
+           2‿2 ↕ a
+
+