Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
A: square template defined by four corners. B: nodes set up with the square template. C: z-arcs Az along the rays. D: r-arcs Ar between the rays (Δr = 0). E: r-arcs Ar between the rays (Δr = 1).
