Well then here's the problem with that analogy then, there is a clear way to move from one gear to another, heck I could even move from 1st to 5th or vice versa, ie we can move from one state to another state and there is no fundamentally necessary transition from one to the other. ie. the relationship between the gears and moving one to another is the full set of pairs that can exist rather than some subset of the pairs.
So we have our set of gears:
{1..5, R, N}
the relationship and changes we can make are as follows
(1,1),(1,2),(1,3),(1,4),(1,5),(1,N),(1,R),(2,1),(2,2),(2,3),(2,4),(2,5),(2,N),(2,R),(3,1),(3,2),(3,3),(3,4),(3,5),(3,N),(3,R),(4,1),(4,2),(4,3),(4,4),(4,5),(4,N),(4,R),(5,1),(5,2),(5,3),(5,4),(5,5),(5,N),(5,R),(N,1),(N,2),(N,3),(N,4),(N,5),(N,N),(N,R),(R,1),(R,2),(R,3),(R,4),(R,5),(R,N),(R,R)
Notice that we have transitions one way and not the other, in contrast evolution must be thought of sequential changes that can't always be reversed as the reversal process generally concerns interactions between two divergent groups before they are sexually divergent.