In the case of the B (or center) pillar on four-door sedans, the pillar is typically a closed steel structure welded at the bottom to the car's rocker panel and floorpan, as well as on the top to the roof rail or panel.
On an average a period lasts between 3 to 5 days. It is normal for a girl to have irregular periods in the beginning. During this time, the duration of her periods may vary from as short as 2 days to as long as 7 days. It can take up to a year for periods to become regular.
The average menstrual cycle lasts 28 days. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 35 to 39.