Hmm...
Lobbing great stones UP is a poor move so the height of the Tor will be a
massive factor agreed. However if anyone is interested in working on this I can
get hold of a program which works as a simulator for trebuchet, onager etc so I
can work out maximum heights of trajectory etc. Remember rocks are not the
only things hurled over walls. Dung, dead animals, dead Oranthi, stone jars of
gorp...
As for the focused light beams this had been tried by Aristotle (I think...)
and by someone like Discovery Channel using polished bronze or copper mirrors.
If my distorted memory is correct they did manage to cause a small row boat
to smolder so it is possible.
Silver would be better as it's more reflective (infact it's the most
reflective metal bar none) and the old runic assossiation.
However as pointed out YOU try getting a cloudless sky with a bunch of Storm
followers just up the road...
Unless you used moonlight...
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