One embodiment of the present invention provides a system that reuses information associated with a constraint solving operation for a problem domain. The vehicles includes a control apparatus for controlling the drive torque of a first drive unit which is associated with a first axle and of the drive torque of a second drive unit which is associated with a second axle. A switch activates the powered unit in the first direction and a first switch is engaged when the spring is compressed to the low level of compression to deactivate the powered unit. A maximum diameter is formed where the reverse taper section and main body section meet on the barrel. The second operation uses at least a portion of the one or more first results generated by the search for the one or more of the plurality of objects. Numerous other aspects are provided.