I have a few questions about the The Roller Coaster - Box Robot. How do you ensure that the starting point for the XY axis is the same for every run? It is easy if you set the opposite actions for each motor at the end of a program, but if the program is interrupted, then it will not return. Is there a way to set a starting point to run at the beginning of each program? Just not sure what that would look like?!? Especially since when the gear reaches the end of the gear rack, it starts clicking? Is the clicking ok? I would think that eventually this would cause a problem??!