Given the autocorrelation function of the signal "s":
$$r(k)=\sum_{t=-\infty}^{+\infty}{s(t)\cdot s(t+k)}$$
The autocorrelation of a rectangular function $\Pi$ (t/2) is a triangle formed by the vector:
$$(..., r_{-3}, r_{-2}, r_{-1}, r_0, r_1 r_2, r_3, ...) = (..., 0, 1, 2, 3, 2, 1, 0, ...)$$
Although the values of $\Pi$ (t/2) are the same between [-1, 1] with the function:
$$z(t)=\begin{cases} 1, |t|\le1/2\\ 0, |t|\gt 1\\ \end{cases}$$
The autocorrelation is different, why?