{≢⍉↑⊆⍨2</,⍵}l → 2.0E¯5 | 0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕
{⌈/≢¨⊆⍨2</,⍵}l → 1.8E¯5 | -12% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕
{1≥≢⍵:0 ⋄ m←2≥/,⍵ ⋄ c←+\~m ⋄ ⌈/c-+\m\+\⍣¯1⊢m/c}l → 6.1E¯6 | -70% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕
{¯1+⌈/¯2-/⍸1,1,⍨2≥/,⍵}l → 1.7E¯6 | -92% ⎕⎕⎕
{¯1-⌊/2-/⍸1,1,⍨2≥/,⍵}l → 1.3E¯6 | -94% ⎕⎕⎕