AES was formed in 1996, at which time it hired eight employees. At a meeting of these employees in 1997, they expressed concern that the company might not survive, as it was using outdated equipment. At that meeting, a company executive asked the employees to remain with the firm and stated that the company was likely to merge with another firm, and if it did, the original eight employees would receive 5 percent of the value of the sale or merger as a reward for staying. In 2001, AES was bought by another firm, and the seven employees who had stayed sought to collect their 5 percent. The company refused to pay on the ground that there was no contract. Did the company and employees have a bilateral or a unilateral contract? Explain. Vanegas v. American Energy Services, 302 S.W.3d 299; 53 Tex. Sup. J. 204 (2009).