An expression is a small piece of code, much like a script— that you can plug into your After Effects projects, that evaluates to a single value for a single layer property at a specific point in time. However, scripts tell an application to do something, an expression says that a property is something
I used a countdown expression to get the countdown effect:
st = 60;
t = st - time;
c = timeToTimecode(t);
c = c.substring(6,8)
c
Wiggle - change positions randomly over time. Using the wiggle expression is often much faster and easier than using the Wiggler.