This looks a lot like how Chinese characters are composed of individual "radicals", arranged like tetris blocks inside the same square box. Some of them affect the meaning of the letter, while others only signify the sound it's supposed to make. The resulting writing system is not easy for foreigners to learn, but it makes quite an efficient use of space. This might have been more valuable at a time when writable surfaces were expensive.

The Korean writing system took the hint, but only uses simple phonetic symbols. Each syllable is expressed as a block-like arrangement of the consonants and vowels it contains. This probably results in less entropy per character than the Chinese system, but perhaps easier to write a parser for.