Personally, I don't think it's that important
What matters is the location of doors and windows, the placement of furniture and the harmony with some natural environments.
If you really want to see Feng Shui, you should find a gentleman.
Look at your house.
You can't say for sure here. . .
About knife-shaped houses
Personally, I think we should put some plants in the upper left corner of the word "knife", which is the position of the tip of the knife.
Preferably green plants.
Anyway, wherever you look unhappy, put plants.
Absolutely.