Why always show artificial flies on a vice, from the aerial world? Is it only to charm the fly fisherman, to lure him? Fish live under the mirror, see under the mirror, swallow under the mirror. These are convincing arguments to refine the abdomen of flies in order to present an anatomical reality, a reality of movement different from the great aerial classics. The neo-behaviouralist school of tying takes on its full meaning and allows progress in the creation of lures. The imagination under the mirror asks questions about the eye of the fish. Let's try to approach it for the game because we can't put ourselves in the eye of a fish. Bubble tests also make it possible to determine the points of connection between the surface tension of the water and the surface of the artificial fly. This helps to optimize positive fly floats by knowing and using the most appropriate materials.