T3 Average, that generalised double average applied three times over. The result reads as smooth as a long moving average while turning close to as early as a short one, which no single exponential average of either length does.

Warmup is the thing to get right here, and it is deeper than the length suggests. One layer is two chained averages, and the layers nest three deep, so the longest term is six averages of averages. Each is chained onto a series that is already na for its own warmup and so starts length - 1 bars after the one it reads (see emaOfGapped), which puts the first printed bar at 6 * (length - 1): index 24 at the default length of 5, not index 4.

Highlighting is a colour on one line, not a second plot: the line is continuous either way and only its paint changes, so a break in the colour must not become a break in the series.