Problem: Duplicate characters

Code: Duplicate+characters/tails_1642045013

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):[chr] 
    + (concat):[chr] 
        . (map):[[chr]] 
            @ (= fstLine):[chr] 
            ^ (replicate):[chr] <--arg( A:chr ) 
                2 (integer):int 
                $ (= A):chr 
    "\n" (string):[chr]