Here are two more exquisite works by Hakuin Ekahu. The first is on the theme of 'one hand clapping' which is the most famous of Japanese koans. The second one is perhaps another koan but I don't know the motif. It is simply called 'mortar and bush warbler'.
These are interesting for me, notably when one thinks of the struggle of the Contemporary painter in his/her search for meaning in the surface especially after someone like Matisse for instance.