A method and system for generating customized incentives involving electronic distribution of coupons to remote personal computers based on proximity of the computer to a retail center are disclosed. The valving is responsive to the representative fuel pressures to control the fuel supply from the second fuel outlet to the second accumulator volume as a function of the fuel pressure in the first accumulator volume. The motor is rotated in the forward direction to drive one wheel train thereby to carry out a mechanical display, and is rotated in the reverse direction to drive the other wheel train thereby to carry out another mechanical display. The present invention relates to an improved porous implant wherein the pores of the implant present a second modeling material on their surfaces. A second wall is joined to the first end of the mounting bracket and extends in a first direction away from the first wall of the locking bracket.