I remember reading that the creator of the original ping command said he was still slightly annoyed decades after that he didn't also invent traceroute at the same time.

I love snippets like this because they're so useful for teaching. Suits the "Socratic/inductive" method of saying "Oh, if only we had a tool that does this kind of route tracing ... Oh wait a minute ... Hmm what's traceroute do?"

They also demonstrate the Unix philosophy that more complex tools can be built from smaller ones.

I glad to see this. I sometimes use this to troubleshoot on remote systems with no `traceroute` available.