Given linear affine functions \( g_i(x,y) := a_i x + b_i y + c \) with \( i \in \{1, \dots, N\} \) describing the piecewise linear boundary of a set \( M \).
A problem could be: Sketch the set \[ M := \{(x,y) \in \mathbb{R}^2 \, : \, g_i(x,y) \leqslant 0, \, i \in \{1, \dots, N\}\}. \]