[bxr]

At a glance it was easy for me, without even seeing the labels, to understand X was hops, Y was RTT and Z was the attempt number.

[rix0r]

But every hop is also a new attempt... and any variance for a hop could also be encoded using error bars.

[bxr]

I didn't say it was a good visualization, just that its not hard to understand what they're trying to convey.