Fig. 3: Experimental observations of topological corner-edge-corner transports.

a An image of the experimental sample. Circular holes are perforated in cavities for inserting the sound probe or point sound source, which are sealed with plugs when not in use. b Zoom-in photograph for the area marked by the red box in a. c The same as b, but for the sample with defects (green dots). Insets give the details of the normal plug (orange box) and plug (green box) with the hard cylinder. The hard cylinder (as a defect) has the same size as that in Fig. 2g, where \(l=2\,{{{{{\rm{cm}}}}}}\) and \(d=0.35\,{{{{{\rm{cm}}}}}}\). d Measured pressure fields (\(f=4.16\,{{{{{\rm{kHz}}}}}}\)) of the sample. Note that the sound signal attenuates as its propagation due to the inevitable absorption. For the clarity of demonstration, the data of each layer are normalized by the corresponding maximum value. e The same as d, but for the sample with defects. The 2D presentations of the data of d and e can be found in Supplementary Fig. 9. The cyan circles and black arrows in d and e represent the point sources and the propagations of sound, respectively.