Heaven and earth in general, there are black holes in the well; Black dogs are white and white dogs are swollen. What does this poem mean?

It describes the scene of a snowy day. When snowflakes fall, the world is white, so it is called the general world. But there are black holes in the wellhead, so there are black holes in the well. The black dog was covered with snow and became a white dog. The white dog is covered in snow and looks bloated. This is Zhang Da's Ode to Snow in the middle Tang Dynasty.

In the mid-Tang Dynasty, there was a painter named Zhang Ming who loved to write such poems. In the Tang Dynasty, his poems were "unique" and attracted people's attention.

For example, his "Ode to Snow" is quite famous: "The mountains and rivers are blurred, the wells are black, the yellow dogs are white, and the white dogs are swollen.

There is not a word of snow in Ode to Snow. Zhang Dayou seems to have used his brain when writing poetry.