Miscellany

flag_levels = [    [],           # Level 0    ['SH'],       # Level 1    ['OO', 'QT', 'HS'], # Level 2    [],    [['CL', 'ST', 'T'], # Level 3    ,],     [ 'SW'],           # Level 4 (same as level 3; no flag change)    [],    ['GM','L'],   # Level 6!]