Conventional but bare trusts: contingency gift over to executors
A deed or will may provide that property is held for an individual, subject to a particular contingency, typically that the individual reaches a particular birthday. Meanwhile he or she is entitled to the income. If he or she dies without the contingency being fulfilled, then the property goes to his or her executors.
In such a case there is in fact only one beneficiary because the personal representatives cannot be regarded as distinct from the individual. Therefore, the individual is absolutely entitled to the property from the outset.