Let $U=[-1,-0\mathrm{.}3][0\mathrm{.}3,1].$ Let $W(x)$:$=1$ and $D(x)=\{\begin{array}{ccc}0,& if\text{x}\text{i}\text{n}[-1,& -0\mathrm{.}3],\\ 1,& if\text{x}\text{i}\text{n}[0\mathrm{.}3,& 1].\end{array}$ Consider the following polynomial approximation of $D(*)$ over $U.$ How many alternation points it has? Comment: Don't use a microscopic vision. Wherever the polynomial is almost touching dotted lines, it is indeed touching it$.$