Special postmarks with famous scientists on cover from South Korea

I got this cover from South Korea with special postmarks dedicated to famous scientists from South Korea: Soon-ji Yi (astronomer), Choi Seok-jeong (mathematician) and Ahn Dong-hyuk (chemical engineer). On fourth cancellation you can see pictograms referring to the works of these scientists.

Stamps on cover:
Japanese Tit (Parus minor), issued on 5.6.2006.
Grand Crinum Lily (Crinum asiaticum), issued on 2.3.2006.
The 150th Anniversary of the Birth of Woodang Lee Hoe-yeong, issued on 21.4.2017.


Than you, Li Ming!