The rule against perpetuities is like a big rule that makes sure that someone's property can't be tied up and kept in the family for too long.
Basically, when someone owns property, like a house or land, they can decide who gets it after they die. But they can't just give it to anyone and everyone forever. There has to be a limit on how long they can control who gets it.
So, the rule against perpetuities says that a person can only say who gets their property for a certain amount of time after they die. This time limit is usually around 21 years after the death of the last person who could have had a child born and alive when the person who made the will or trust died.
This may sound confusing, but it's important because it means that no one can control a property for too long after they die, which can cause problems for future generations who may want to use or sell the property. The rule against perpetuities helps make sure that property can be used, sold, or given away fairly and reasonably to people who want it.