I opened a 3-gang box and found that the three switches in the box were connected by one black wire, not three black wires coming from one nut to the three switches. One black wire literally goes from the first switch to the second to the third. A section of the wire insulation was removed and the exposed wire circled around the screw of a switch. This is how the three switches wired.
I know it works but wonder whether this is a good practice. Does the code say one has to use a wiring nut?