This will be interesting to hear from guys but they way I was taught is that your FF sends out wave lengths on a cone shape so it is a triangle. As the fish or item comes into the cone it marks a dot on the screen. When it first comes into the screen it is the furthest distance from the transducer. As you pass over the distance shrinks moving the dots upward then as it goes out other side of cone it gets further away giving it the distinct arc we see on screen. Hope that makes sense Sent from my SM-N920V using Tapatalk