Accessory is the normal spelling of the word to mean something extra or additional: The vacuum cleaner had several accessory parts. In the legal sense, however, the spelling accessary is sometimes found: She was charged with being an accessary to the crime (she had taken a part in it). In the USA, accessory is the spelling for both senses.
The temple of Angkor Wat had five towers but often only three are depicted. Red and blue recall the earlier flags of Cambodia. Effective date: 20 June 1993.