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).
Constructive interference is when two or more waves combine, and the amplitude of their resultant wave increases. Destructive interference is when two or more waves combine and the amplitude of their resultant wave decreases. Waves will also diffract. Diffraction is the bending of waves when they hit a barrier. Sound is the result of vibrations in molecules causing the molecules to compress and retract, making sound a longitudinal wave.