;/#
#/;

a/#
#/a

/;/#
#/;/

/#
    Ok, so this should give no output either
#/

# ;
#a
# /;

; # stuff
a#
/;#
# ;/
;/

# More intricate block changing checks

/# Comment start
Comment end #; if (thing)
;; else if (other_thing)
;# Comment start
End #/