Mechanical word
= Mechanical word
For slope $0\le\alpha\le1$ and intercept $\rho$, the lower mechanical word has letters $w_n=\lfloor(n+1)\alpha+\rho\rfloor-\lfloor n\alpha+\rho\rfloor$. These letters are zero or one. Replacing floors by ceilings defines the upper mechanical word. An irrational slope gives a <Sturmian word>.