add text object
initial visibility invisible
add event:
every 1 second
condition: compare text.txt equal to 0 - invert
condition: compare text.txt equal to "GO" - invert
action: set text.txt = int(text.txt) - 1
action: set text visible
sub
condition: compare text.txt equal to 0
action: set text.txt = "GO"
action: wait 1 sec
action: set text invisible
action: set text.txt = 0
The above is a functional countdown timer with only a text object.
As soon as you set text.txt to anything bigger then 0, then it appears and starts counting down to 0 and says Go.