A Special Assessment District (S.A.D.) is a geographic area in which the market value of real estate is enhanced due to the influence of a public improvement and in which a tax is apportioned to recover the costs of the public improvement.
Void, voidable, and unenforceable contracts: (1) A void contract is one without any legal effect from the beginning. (2) A voidable contract is one that a party may elect to avoid or ratify. (3) An unenforceable contract is one otherwise valid but for which some defense exists extraneous to formation.
A unilateral contract is one in which there is a promise to pay or give other consideration in return for actual performance. (I will pay you $500 to fix my car by Thursday; the performance is fixing the car by that date.) A bilateral contract is one in which a promise is exchanged for a promise.