draw on butter or carve ice
Painting on water and carving on ice, a Chinese idiom, Pinyin is Hu à Shu à L à UB à ng, which means painting on water and carving on ice. It's a metaphor for working in vain. From new theory.
Analysis of Idioms
Painting and painting
The origin of Idioms
Huan Tan's Xin Lun in Han Dynasty: "painting water and carving ice, dispelling with time."
Idiom usage
Used as an object or attribute; used in dealing with affairs.
draw on butter or carve ice
pull up enemy flags and behead enemy generals on the battle field - qiān qí zhǎn jiàng
Different ice and charcoal vessels - bīng tàn bù tóng qì
to pick the good and select the capable for public posts - xuǎn xián yǔ néng