This diagram represents the Fee Simple Defeasible, which comes with a Possibility or Reverter. For example, “so long as premises are used for school purposes.” The reversion happens automatically–no need for the grantor (or his heirs) to take any action.
This diagram represents the Fee Simple Subject to Condition Subsequent, which comes with a Right of Re-Entry. For example, ” but if the premises are not used for school purposes, the grantor has a right to re-enter and retake.” Unlike the Possibility of Reverter, the Right of Re-Entry requires the Grantor (or his heris) to take actin, and re-enter the land.
This diagram represents the Fee Simple subject to an executory interest, which comes with an executory interest, which is vested in a third person, instead of the grantor. For example, “O to “School board, but if it cease to use the land as a school, to the Library.”
This is the grant at issue in Mahrenholz:
“this land to be used for school purposes only; otherwise to revert to Grantors herein.”
This is the school at issue in the article about the Maeser School.
Here is a picture of the Odd Fellows building: