CS of model of prototype of twin propeller flying machine (Alexander Graham Bell invention; 0:09). CU through magnifying glass of machine punching chip board (0:22). CU of circuit board being modified (1:11). CU of readings on oscilloscope (1:17). CU of control panel of oscilloscope (0:22). CU of eye looking into microscope (0:18). CU of electronic component being inserted in glass tube (0:25). CU of lasers (1:24). CU of digital counter running, CS of panel of Digital POP-8/1 computer, CU of wires (1:34).