SKI 2022 Ekoline Ultrasonoscope Ultrasound imager. The monitor and printer probably need a scanning probe to show something. The ultrasound machine itself worked very well.
It was tried on a shorter bottle with water, a taller bottle with water and a 324 mm long piece of Aluminum sheet metal. In the shorter bottle a second echo (surface - bottom again) is visible. In the Aluminum plate, two such reflections are easily visible. See the pictures of this, in that order! We even got a clear reflex from the from panel in air, at some 3 inches distance!