The typos in couplets are quite reasonable and contain unexpected wisdom.

This is a couplet of Xidi ancient residence in Gan County, Anhui Province. We only read couplets, not typos.

On the first line, happiness comes from hard work;

Downstream, cheaper and more self-defeating.

This couplet is very common. Pupils are not very creative in writing, but four of the words 14 in this couplet are typos.

And this typo contains profound meaning. Please look at the picture below. I have listed all the typos.