Hello,
I am trying to create an obstacle for my custom obby scenario. I want it to be like a stop and go light. Let me illustrate:

- = palisade walls
c = cliff

c----- -----c

In the above illust. the two wall units next to that space in the middle (in bold) i want to change possession: they start as red's (stop light) and change to green's (go light) after like 5 secs. Then they change back to red's after 5 secs and so on (they loop). i can't seem to get this mechanism to work, though.

The idea is that if the unit tries to pass through while it is red, he dies, but can pass through green.
Can somebody help me??
Thanks
p.s. if you have questions, please ASK!!