Synchronized vertical line tool tips on small multiples

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I came across this amazing graphic on The Economist website: https://www.economist.com/graphic-detail/coronavirus-excess-deaths-estimates and this idea came up: synchronized vertical lines with markers and their corresponding data labels when you mouse over on any of the lines of the small multiples. Because all the multiples share the same x-axis (date), by having all the vertical lines appearing at once when you mouse over, it aids in making visual comparisons of the data values sharing the same date in all small multiples. In addition, maybe an option of switching between a tool tip or a data label when you mouse over on the line visuals.

Please refer to this video: https://www.youtube.com/watch?v=Fxf-6Qvj2PE - where you can see this idea of Synchronized vertical line tool tips on small multiples along with second item above that when you mouse over, the official and estimated figures show up according to their corresponding date. The data labels appear of the left of the vertical lines and very close to their corresponding data markers. Subtle but prominent.