is a general algorithm for finding solutions to some computational problems, notably constraint satisfaction problems, that incrementally builds candidates to the solutions, and abandons a candidate ("backtracks") as soon as it determines that the candidate cannot possibly be completed to a valid solution. wikipedia 
Backtracking works on the principle of depth-first search
Backtracking proceeds according to the Trial and Error principle, i.e., an attempt is made to expand an achieved partial solution into an overall solution. If it is foreseeable that a partial solution cannot lead to a final solution, the last step(s) is/are retracted and alternative paths are tried instead. This ensures that all possible solutions can be tried (principle of the Ariadne's Thread). With backtracking algorithms, an existing solution is either found (possibly after a very long runtime), or it can be definitively stated that no solution exists. Backtracking is for most part most simply implemented recursively and is a prototypical use case of recursion.
~
Jeff Miller via matrix : "Ariadne's Monkeys". (after scanning the entries above, pulling traversal threads through a wiki labyrinth)
The Principle of Critical Action and the Harmonic Oscillator – **Ariadne’s Thread** in Classical Mechanics. pdf
> In all fields of physics, one encounters Oscillating Systems
DOT FROM lambda-browsing