/ / pi\ / pi \\ Or|And|0 <= x, x < --|, And|x <= pi, -- < x|| \ \ 4 / \ 4 //
((0 <= x)∧(x < pi/4))∨((x <= pi)∧(pi/4 < x))
pi pi
[0, --) U (--, pi]
4 4
x in Union(Interval.Ropen(0, pi/4), Interval.Lopen(pi/4, pi))