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.
Experiment user interface: 1 is for slow horizontal movement, 2 is for rapid horizontal movement, 3 is for slow vertical movement, and 4 is for rapid vertical movement. The double arrow in the figure presents the direction of each relative movement. Adapted from [24].
