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.
Formation of bridges (pairs of green circles) due to (a) direct bonding of two open stickers (red circles) across the interface; (b) hopping (partner exchange) of an open sticker (depicted by a red circle) across the interface by converting a loop into a bridge, while keeping the number of open stickers unchanged.
