x←?1e5⍴2e9 i←(¯1+⍴x)-⍳⍴x x[i]≡⌽x 1 cmpx 'x[i]' '⌽x' x[i] → 5.45E¯4 | 0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕ ⌽x → 2.29E¯4 | -59% ⎕⎕⎕⎕⎕⎕⎕⎕