The way wig wags animate.

Hi,

I'm building some wig wags to add into an airport sim. At the moment, I know they are two amber lights which alternate at about 30-60 cyles per minute.

My question is, when they are on both sides of the stop bar, do they animate in a particular way. For example, as a rough drawing ( zero = off, one = on)

10 ____________ 01
01 ____________ 10
10 ____________ 01

OR

10 ____________ 10
01 ____________ 01
10 ____________ 10

The first one shows both sets of wig wags, flashing either towards/outwards of the center, or with the second one, shows them flashing from the same start position.

Thanks.