The 'ideal square' of logographic scripts and the structural similarities of Khitan script and han'gul

A comparison of the Khitan Small Script and Korean han'gŭl shows a striking structural similarity of two essentially phonetic scripts that combine 'letters' into large blocks. These blocks in han'gŭl correspond to the syllable, whereas in Khitan they correspond to the word-level. I shall compare these two systems structurally with both the linear alphasyllabic principle of Brahmi-derived scripts and the principle of an 'ideal square' (or 'ideal oblong') that characterizes Chinese, Egyptian or Mayan logographic scripts in order to establish why the Khitan and Korean scripts share a rare structural principle.