sorry it's 3, i edited the previous post (i have so many sheets i sometime open the wrong revision), additionally i was not using that burn AVERAGE value in the % values i gave in those posts.
if you interested it uses the Infinite geometric series
http://en.wikipedia.org/wiki/Geometric_progressionyour burn will average a damage of 1 for a turn (0,1,2 average to 1).
and the chance that it will still be able to role on the next turn is 2/3 (ie not a 0)
which comes to Sum = 1/(1-2/3) = 3
