The ancient japanese culture that used cords to mark pottery was the... “Jomon Period”
I believe the answer is: Sheet metal
Self tapping screws are made by creating a gap in the connector within the thread of a crew, which creates a flute and cutting edge just like what we see on tap. This makes self tapping screws able to tap their own hole in a sheet metal while normal screws can't.
In most states, other leaders in the executive branch are also directly elected, including the lieutenant governor, the attorney general, the secretary of state, and auditors and commissioners.