1.	To A for life, then to A's children for their lives, and on the death of the last survivor of A's children, to B in fee simple. (At the time of this disposition A has two very young children and is capable of having more children in the future.)

•	O has nothing. 
•	A has a life estate.  
•	A’s children have a vested remainder subject to open in a life estate
•	Unborn children have an executory interest. NO SUCH THING AS A EXECUTORY INTEREST SUBJECT TO OPEN OR CONDITION SUBSEQUENT.
•	B has a vested remainder in fee simple and does not break the rule of perpetuities. (it is vested from the beginning) 
2.	To A for life, then to B, but if at B's death she is not survived by children, then in that event
to C.
•	O has nothing
•	A has life estate. 
•	B has vested remainder subject to complete divestment, 
•	C has an executory interest.  (A + B is the measuring life for C’s interest)

3:	To A for life, then to such of A's children as attain the age of 21.

•	O has a possibility of reversion

•	A has a life estate 

•	A’s children have a contingent remainder subject to open (May die and other children may be born)

•	Unborn children have a contingent remainder subject to open. 

•	No rule is violated because of the gestation period being added to the 21 year vesting limitation.

4.	To A for life, then to such of my nephews and nieces, as attain the age of 21, (The grantor's parents are still alive.)

•	O has a possibility of reversion  (possible that all nephews and nieces could die before 21)
•	A has life estate
•	Nieces and nephews have a contingent remainder (O’s parents could have more kids and they could have kids which would be nieces and nephews and diminish the amount of the interest) Once they reach the age of 21 Niece’s and Nephew’s interest becomes a vested interest subject to open for each, as they turn 21.
•	Unborn Nieces and Nephews have a executory interest subject to condition subsequent 
•	Rule is violated because A could die and parents could have children who would not be a “life in being” as of the date of conveyance and they could not vest within 21 years plus a “life in being”
5.	0 conveys Blackacre to School so long as used for 'educational purposes, and when it is no longer so used, to A. 
•	O has possibility of a reverter.
•	School has a Fee simple subject to limitation. Becomes a fee simple determinable when A violates rule.
•	A has a executory interest which (unless they are another charity) violates the rule because it may never vest AND thus O retains a possibility of reverter (it automatically reverts.
6.	To A for life, then to 'such of A's children as live to attain the age of 25. At the time of this disposition, A has two children: X (age 12) and Y (age nine).

•	O has a possibility of a reversion
•	A has life estate
•	A’s living children X and Y have a contingent remainder. This interest will become a vested remainder subject to open when they reach age 25 unless A dies before then.
•	A’s unborn have a contingent remainder which may not vest with life in being (all lives in being could die tomorrow) plus 21 years and this violates the rule and destroys the interest in A’s children 
7.	Suppose, in the preceding example, X and Y were age 24' and 22, respectively, and A was a 60- year-old woman.

•	O has a possibility of  reversion
•	A has life estate
•	A’s living children have a contingent. This interest will become a vested remainder subject to open when they reach age 25
•	A’s unborn (BIOLOGICALLY IMPOSSIBLE DOES NOT MATTER) have a executory interest which may not vest and this violates the rule and destroys the interest in A’s children. The age of A is not a factor and it is always assumed a living person could have more children.
8.	To A for life, then to his widow for fife and on the death of A's widow, to such of Ais
descendants as. are then living:
O has a reversion
A has life estate.
Wife has contingent remainder in a life estate but who this is, is not fully ascertainable ( wife may change due to divorce) Since second wife could be a as yet unborn person she would not be a “life in being” today. 
Descendants have a vested remainder subject to open
It violates the rule do to the possibility of the wife’s status as a possibly not a life in being. 
9.	A is a Subdivision developer, and gives B an option to purchase a lot in the subdivision be exercised within 60 days after the City Council grants approval for the filing of a subdivision plat," 
B’s interest violates the rule because it is possible for the city to grant the filing of the plat in greater than a life in being plus 21 years.