Take a step forward and then backward. Currently at step zero, following the sequence: 
Move one step ahead and one step back. Step index is 0, step order as follows: 
Advance one step forward, then retreat one step. The step count stands at 0, with this order: 
Step forward once, then step backward once. You’re on step number 0, in this particular order: 
Progress one step, then reverse one step. Step number zero is current, maintaining the order: 
