Problem: code golf meetup 2025

Code: code+golf+meetup+2025/whio_1749502772

Nibbles version: 0.2 | 0.21 | 0.22 | 0.23 | 0.24 | 0.25 | 1.00

Format: Compact | Simple | +Type | Table | JSON | .nbl (DeBruijn) | .nbl (names)

+ (concat) 
    . (map) 
        `= (chunk by) 
            @ (= fstLine) 
            $ (= A) <--arg( A ) 
        > (drop) <--arg( B ) 
            - (subtract) 
                ~ (auto = 1) 
                , (length) 
                    $ (= B) 
            : (append) 
                (implicit arg = B) 
                (implicit arg = B)