From before I was born until I was 13 my dad worked a swing shift at this plant. His schedule was in two week intervals- 2 weeks on the day shift, then 2 weeks on the night shift. They were 12 hour days too.

His schedule was:
Mon: 7pm-7am
tues: 7pm-7am
wed: off
thurs: off
fri: 7pm-7am
sat: 7pm-7am
sun:7pm-7am
mon: off
tues: off
wed: 7pm-7am
thurs: 7pm-7am
fri: off
sat: off
sun: off

Then the next 2 weeks were the some schedule only he'd work days from 7am-pm.