x1=c1 is a bow/crossbow/ballista for shooting ammunition x2=c2 [arrow/quarrel/crossbow bolt] by flexing and releasing bow/prod/lath x3=g1 of material x6=g3, to whose two ends are tied bow string x4=g2=s1 of material x5=s2.
To be clear, the launch mechanism is as follows: x4 is pulled so as to bend x3, while x2 is placed on x4, and x4 is released, causing x3 to snap back into its normal shape, launching x2 as it does so.