calc, 209 bytes

Result

AC

Duration

1795ms

Code [DL]

=SUBSTITUTE(SUBSTITUTE(A1;RIGHT(LEFT(A1;FIND(CHAR(10);A1)+FIND(CHAR(10);A1));FIND(CHAR(10);A1));LEFT(A1;FIND(CHAR(10);A1)));CHAR(75);REPT(CHAR(75);1+FIND(CHAR(84);A1)-MOD(FIND(CHAR(75);A1);FIND(CHAR(10);A1))))

stdin

                                           T      
                                                  
                                                  
                                                  
                                                  
          K                                       

stdout

                                           T      
                                           T      
                                           T      
                                           T      
                                           T      
          KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK                                       

stderr

javaldx: Could not find a Java Runtime Environment!
Warning: failed to read path from javaldx
convert /tmp/code.csv -> /tmp/out/code.csv using filter : Text - txt - csv (StarCalc)

strace