Say you pick a point \((x, y)\) at random in the unit square \(0 \leq x \leq 1,0 \leq y \leq 1\). Compute the probability it will be in the set
\[
S=\{x \leq y, \quad \text { and } \quad x \leq 1 / 2, \quad \text { and } \quad y-x \leq 1 / 2, \quad \text { and } \quad 1-y \leq 1 / 2\}
\]