I once experimented with the tool "quirk" and came to a gate, whose function I can not properly tap into. I'm working in the circuit with 4 bits, the last bit is negated, so from 0 to 1. On all 4 bits then I apply a Hadamard transformation. Then this special gate is used, whose function I can not explain.
Hence my question. Can someone explain what makes the gate? How does this work? I know so far the CNOT gate and the Toffoli gate, but this one seems to be something else?
I hope the question is understandable.