I’m partial to the 74x153 myself.

Indeedy. Aren’t they great?

One is baffled.

Two are baffled.

Was there a question here?

One Guy, Two Guy
Nan- Guy, Q- Guy

What could be more logical?

If I understand correctly They’re talking about 74153 TTL chip (the x is for the specific logic family, like LS for Low Power Schottky, etc.) It’s a Dual 4-Line to 1-Line Data Selector/Multiplexer. Each multiplexer has 4 inputs. If you address one of the multiplexors with a binary number from 00 to 11, it will output the data from the corresponding input