Arlington County has an extensive network of bicycle infrastructure, including 50 miles of shared-use off-street trails. These multi-use trails are generally 10 feet wide with a solid yellow line striped down the middle to separate users.
Constructive mathematics. Idea. Broadly speaking, constructive mathematics is mathematics done without the principle of excluded middle (or other principles, such as the full axiom of choice, that imply it).
something so reflected, as heat or especially light. Mathematics. (in a plane) the replacement of each point on one side of a line by the point symmetrically placed on the other side of the line. (in space) the replacement of each point on one side of a plane by the symmetric point on the other side of the plane.