L tr

L trL trL trL tr
L trL trL trL trL trL trL trL tr
L trL trL trL trL trL trL trL trL trL trL trL tr
L trL trL trL trL trL trL trL trL trL trL trL trL trL trL trL tr
L trL trL trL trL trL trL trL tr