Just as important as the outfit we sleep in, is also the environment.
My ever practical parents were harried, hard working blue-collar folks who had little time to themselves let alone raising a daughter and a son. So they have solutions to everything!
Issue: Sleeping kids do not lie still! They do cartwheels, karate kicks, and punches in their sleep; tossing blankets off again and again.
My parents must have gotten pretty annoyed of checking on my active brother and I every few hours, repositioning the blankets constantly, that they had an "Eureka!" moment. After all necessity is the mother of invention and my mom was quite a talented seamstress.
Solution: The "blanket bag"!!!
Almost like a burlap sack but not quite. My mom literally sewed together 2 pieces of fabric together, leaving a hole on top for the head, the two sides for arms, and a zipper on the side.
For the winter, she used stiff heavier material to brave the cold so we look more like rectangle monsters:
But what about mobility you ask?! Since the original versions had no holes for feet we just hopped around and bent over like worms:
Later one she upgraded the product and opened holes on the bottom.
Soon I was running around terrorizing my younger brother like this: