Average Directional Index is a way to determine trend strength (and whether there is a trend). One of the caveats is when you have trendless conditions on a higher timeframe. You can get whipsaw conditions on the current timeframe in that case.
The purpose of this script is to put ADX into the context of a higher degree trend on a single indicator.
リリースノート
See original post and comments for more details. Updated version has a new visual style. I'm playing with showing trend strength like a heatmap. The lines are now area style. Some may like the more traditional view better, we'll see. I've also tweaked some of the upper timeframe calculation.