In this type of contract, the elements are not specifically written or expressed. In fact, this type of contract is used as a remedy in a situation when one party to the quasi-agreement received unjust enrichment resulting from not paying for a product or service rendered.
A Drupe is a single fleshy fruit with a hard stone which contains the single seed. This is a Cherry (Prunus avium). Other fruits of this type are: Apricot (Prunus armeniaca), Plum (Prunus x domestica), Coconut (Cocos nucifera), Olive (Olea europaea), Peach (Prunus persica), Sloe (Prunus spinosa).
Pistachio-bunch. Pista fruit, in fact, is a drupe (fruit with a large, central located single seed), and it is this seed kernel is what actually edible pistachio nut. Each season, the tree bears heavy clusters of fruits which appear somewhat like that of a grape bunch.