canvas, 122 bytes

Result

WA

Duration

824ms

Code [DL]

for(a=Buffer.from(this.inputs.join(''));i+51<a.length;)a[i+51]|=a[i++];for(;a[++i]!=116;)a[i]|=a[i-1];console.log(""+a)＃

stdin

                                  T               
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                    K                             

stdout

for(a=Buffer.from(this.inputs.join(''));i+51<a.length;)a[i+51]|=a[i++];for(;a[++i]!=116;)a[i]|=a[i-1];console.log(""+a)

stderr

for(a=Buffer.from(this.inputs.join(''));i+51<a.length;)a[i+51]|=a[i++];for(;a[++i]!=116;)a[i]|=a[i-1];console.log(""+a)@0-118: ["for(a=Buffer.from(this.inputs.join(''));i+51<a.length;)a[i+51]|=a[i++];for(;a[++i]!=116;)a[i]|=a[i-1];console.log(""+a)"]
＃@119: ["for(a=Buffer.from(this.inputs.join(''));i+51<a.length;)a[i+51]|=a[i++];for(;a[++i]!=116;)a[i]|=a[i-1];console.log(""+a)"]

strace