This is a seal on a painting. I have identified several but 8 are still unknown. Please can anyone read this seal?
imo, these character are in non-stardand small script; my best guess:

the bottom right is "春" (u+6625)

http://humanum.arts.cuhk.edu.hk/Lexis/lexi-mf/search.php?word=春

top left is "堂" (u+5802)

http://humanum.arts.cuhk.edu.hk/Lexis/lexi-mf/search.php?word=堂

bottom left is "製" (u+88fd)

http://humanum.arts.cuhk.edu.hk/Lexis/lexi-mf/search.php?word=製

top right character, not yet recognised :(