Otto gives Blackacre "to Adam for life, then to the first child of Adam to attain the age of 21 years." Adam has no children at the time of conveyance.

Otto gives $10,000, "to each of my children who marries." Otto has one son, Adam, who is 21 and unmarried at the time.

Olga devises $10,000 "to each of my grandchildren who reaches 21." Olga has one child, Adam, who is 19.

Olga conveys $10,000 "to each of my grandchildren who reaches 21." Olga has one child, Adam, who is 19.

Otto leaves "$1,000,000 in trust, the income to be paid to my son Adam during his life, and the corpus and unpaid income to be distributed to the Buffalo Bills upon winning the Super Bowl."

Otto leaves "$1,000,000 in trust, the income to be paid to my son Adam during his life, and the corpus and unpaid income to be distributed to the Buffalo Bills if they win the Super Bowl within 21 years after Otto's death. Otherwise the corpus and unpaid income are to be divided equally among my issue then living." 

Olga conveys Blackacre "to Ann provided that the property is used to operate a retail lumberyard, but if it is not so operated, Olga and her heirs have the right to  repurchase and reenter said property within one year of the time the specified use ends. The repurchase price shall be for the price originally paid by Ann adjusted by changes in the consumer price index since the time of said purchase."

Otto leaves Blackacre "to Adam for life, then to the first child of Adam to marry." Adam has two children, Connie and Dan, at the time of Otto's demise (and devise).

Otto devises Blackacre "to the first of my grandchildren to marry."

Otto devises Blackacre "to the first of my grandchildren to marry during the perpetuities period."

Otto devises $10,000 "to each of my grandchildren to shake hands with Jay Leno or David Letterman on television." He has two children, but no grandchildren at the time of his death.

Otto devises Blackacre, "to Adam for life, then to his widow for life, then to their eldest surviving child."

Otto devises $100,000 to "Amherst Central High School, when a graduate of that school matriculates as a student at King's College, Cambridge."

Otto devises $100,000 "to my first grandchild to win a lawsuit against Bill Gates." Otto has three children and five grandchildren at the time of his death, but all of the grandchildren are under the age of 21.

Olga conveys "to Ann for 21 years, then to Betty for life, then to my oldest descendant then living."

Olga conveys "to Ann for 21 years, then to my oldest descendant then living, then to his or her oldest child then living."