move to next/previous sibling form

[Mouvedia]

//example 1
[
  [ xxxx ]
  xx|xx
  [ xxxx ]
]
//go to next
[
  [ xxxx ]
  xxxx
  |[ xxxx ]
]

//example 2
[
  xxxx
  [ xx|xx ]
  [ xxxx ]
]
//go to next
[
  xxxx
  [ xxxx ]
  |[ xxxx ]
]

//example 3
[
  [
     xx|xx 
     [ xxxx ]
  ]
  [ xxxx ]
]
//go to next
[
  [
     xxxx 
     |[ xxxx ]
  ]
  [ xxxx ]
]

//example 4
[
  [ xxxx ]
  xx|xx
  [ xxxx ]
]
//go to previous
[
  |[ xxxx ]
  xxxx
  [ xxxx ]
]

I hope the examples are clear enough.