[Math] Least common multiple (LCM): simplest explanation

Sometimes you stuck in traffic jam and watch yellow turn signals of other vehicles.
Very often, blinking periods of two vehicles near each other are not the same.
For example, there are two vehicles.
One blinks yellow signal in each 600ms.
Another blinks its in each 500ms.
Sometimes you see how these signals coinciding.
And you wonder,
can you calculate their 'common' period, when both signals will match with each other?

Let's try to calculate it graphically:

XxxxxxXxxxxxXxxxxxXxxxxxXxxxxxX
XxxxxXxxxxXxxxxXxxxxXxxxxXxxxxX

LCM[500,600]=3000, or 3 seconds.
Each 3 seconds, you will see both yellow signals coinciding.

To calculate a period of signals coinciding of 3 vehicles stuck nearby:
LCM[LCM[vehicle1, vehicle2], vehicle3]
or, in Wolfram Mathematica:
LCM[vehicle1, vehicle2, vehicle3]