Ricocheting shots is an insanely difficult trick.  The formula I use for
determining the penalty for a Ricochet shot is:

E(# of Richochet in Series) * (Modifier of Surface on that Ricochet) = Total
Modifier

Surfaces are rated on a scale from Easy to Act of God.

+1 - Easy (A mirror for bouncing a laser)
+3 - Difficult (Stone walls)
+5 - Extreme (Wooden walls)
+7 - Impossible (Paper walls)
+9 - Act of God (Jello Molds)

Thus, if someone wished to bounce a laser beam off a mirror, then off a jello
mold to shoot a hostage taker in the back of the head, the total ricochet
modifier would be:

(1)*(+1) + (2)*(+9) = +19

Good luck.  I hope you've got a huge bonus, or some Hero Points to spend.  If
you're fond of Ricochet shots, I definitely suggest taking the Ricochet Shot
ability, which lowers all the modifiers on the above table by 1, to a minimum of
1.  IE, if the shooter above had two levels of Ricochet Shot, the penalty would
have been:

(1)*(+1) + (2)*(+7) = +15

Still not an amazing chance of success, but certainly better than +19.