http://apod.nasa.gov/apod/ap160717.html

The racetrack analogy applies to Mercury as it does to Venus although Venus gives observers a clearer view as it runs its circuit along with its phases -

http://www.popastro.com/images/plane...ary%202012.jpg

An evening appearance of Mercury represents its orbital course when it emerges out from behind the Sun to its widest point seen from a slower moving Earth before turning back in while a morning appearance is when it passes in front of the Sun and moves to its widest point in the opposite direction.

The people at NASA/APOD need to grow into adults as Mercury doesn't "trail or lead the Sun", the Sun is stationary and the planet moves .