Creating lightning bolt effects
Both of your versions will probably generate the same IL code. See: https://stackoverflow.com/a/7383090/2655508  

The first version is still better, because you should declare variables as near as possible to their usage.  



You shouldn't shorten variable names. You already have positions[] so why do you have pos instead of position?  



You have some magic numbers in your code which should be extracted to some constants with meaningful names.