A more thorough explanation:

The Rule Against Perpetuities is a legal principle that applies to property ownership. It states that any interest in land is only valid if it must be vested within 21 years after the death of a person who was alive when the interest was created. This means that any interest in land that may not be vested within this time frame is considered invalid.

For example, if a person creates a will that leaves their property to their grandchildren, but only if they graduate from college, this condition may not be valid under the Rule Against Perpetuities. If one of the grandchildren does not graduate from college until 25 years after the death of the person who created the will, then the condition would not be valid.

The purpose of the Rule Against Perpetuities is to prevent property from being tied up in legal limbo for an indefinite period of time. It ensures that property can be bought, sold, and transferred without any legal complications.