from the results.the draw increases steadily to end of draw. i.e. no let off like on a compound.pretty much like a normal flatbow though much more complicated for a flatbow.that back bow basically "helped" a weaker main bow. they used a flat bow. as well as the double bow. in pictures the double bow does look like a sapling split down the center like i mentioned earlier. quite a few years ago i built one like this.2 flatbows tied together, though i used hemp strings. i was hoping Half eye found a different outcome. i was hoping thered be something more than a way of strengthening a weaker bow. heres why i think that double bow was made. to use a sapling. yes they made a flatbow as well. but keep in mind the tools in use at that time. bone, stone, shell, and horn, not to mention wood. o.k. its easier to make a bow from a sapling with these kind of tools rather than cutting down a 8 inch diam. tree , or worse yet, trying to split out a stave from a erect standing tree. not saying it cant be done, it was a lot. but human kind has for all eternity used everything they could. and took the simplest route to get there. face it its just the way we are. not saying we dont get very complex when we have to, but when we find a easier way, yep we are on top of that. case in point modern manufacturing. build it faster cheaper easier. thats us.just my thoughts. it is a sweet bow Half eye. it is somthing to be proud of. not a lot of people have succeeded with that design.you gave me the inspiration to try this again myself.this spring hopfully i find a long straight sapling. and try it tillering it like i mentioned earlier.its still a puzzle but we are much closer now.Tony