Baruch Hashem Adonai בושאהמשהוהי

In Genesis 7 and 8 there is an example of this "mirrored" or
symmetrical structure that is being used in describing the flood.

7:4 - 7 days to wait for the flood
7:10 - - 7 days to wait for the flood
7:12 - - - 40 days of rain
7:24 - - - - 150 days of the waters rising
8:3 - - - - 150 days of waters retreating
8:6 - - - 40 days of waiting
8:10 - - 7 days of waiting
8:12 - 7 days of waiting

Chiasms