

Let's talk about the following hypo:
Grutz, the owner of Blackacre in Fee Simple Absolute, conveys it:
"To Andy Sipowicz and his heirs so long as the land is used only for residential purposes, but if the land is put to non-residential use during Andy's lifetime, then to Jack Bauer and his heirs."
What is the state of the title?
Now apply the Rule Against Perpetuities.
PS That is actually Curt Schilling (not Jack Bauer), but he looks a little like Jack doesn't he?