Yup. At some point there was a storm in a teacup in the dataviz community about the name of the plot, because someone discovered the plot, discovered Joy Divisi

Yup. At some point there was a storm in a teacup in the dataviz community about the name of the plot, because someone discovered the plot, discovered Joy Division, and learned of the origins of the name -- then immediately had to get offended and mount a crusade about it. Luckily, "ridgeline" does describe the plot type quite well, maybe even better than "joyplot".