Specs:

Design and construct a piece of exercise equipment that can shift back and forth between being a stepper ("StairMaster") and an stationary bicycle ("ExerCycle").

The device so designed can fit under a desk, and the a person can be sitting in a chair when using it.

The time required to shift from one mode to the other must be less than 10 seconds and involve no more than two hand manipulations ("gear shifts"). The feet must stay in the same forms (stirrups) during the shifting.

The StairMaster will have two stands across from each other and be able to bear 200 lbs of weight.

The ExerCycle will behave like a bicycle (feet 180 deg out of phase) and have a way to increase or decrease the rotational drag of the action.

The parts for the machine will cost less than $500.