I now have six plus voodoo dolls. What are they good for?

The bridge down in the vault is being a pain. I have been able to jump three sections but can't get across the fourth. Could someone describe or point me to any discussion on just what the three switches are doing in each control room so I can get enough platforms up to jump the fourth one?

Thank you.

go back to all three sets of bridge controls,
keep close eye on what your moving and where
you have to go. I think the voodoo's have a
one time use spell.