Problem: interleave first every third

Code: interleave+first+every+third/whio_1723575547

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)

(implicit string concatenation) 
    ; (save) -->let( B ) 
        `( (uncons) -->let( A ) 
            ;_ (= allInput) 
    * (join) 
        : (append) 
            $ (= B) 
            ~ (auto = []) 
        `/ (chunks of) 
            ~ (auto = 2) 
            (implicit arg = A)