so it's like a rowing boat so what you have is you don't only have the motion of a lot of people think the bird's dude like the up and down movement but you also have the movement that's like a rowing boat so a little bit like this and so what we really want is that the wing. can make a flexible motion so it should be able to really move like this so those motions are really needed for flapping wings light. the engine is soon found out that attempting to copy nature brings its own challenges for an airplane for example it is very easy to make a small scale model and the put it in the wind tunnel and then to calculate everything this related to the aerodynamics before bird this is difficult because you cannot put a real bird in the wind so i know you're going to do these measurements so you really have to learn from how to do this in nature. they also copied the shape of