The Father-Son Bow, Double-Bow, or Penobscot Bow of the Penobscot Native Peoples of what is now Maine, has shorter bow attached to the back of a larger bow. This acts as a primitive pulley system seen on modern compound bows and adds to the draw weight (poundage) of the larger bow.
This one is made of harvested hickory, with sinewed back, waxed nylon string, and rabbit fur silencers. Approximately 48" long, 40# at 28" draw with smaller bow attached. Smaller bow is sinew backed and covered with python skin.
This version is stylized and took a few days to make for what was supposed to be an upcoming independent local film 'Emma's Revenge'.
However, one can be created with enough cordage from sub-prime materials in about 1/2 hour in a survival situation.