This simple script applies the DMI/ADX (trend) indicator to the Bitcoin Dominance Index (BTC.D) to check whether BTC is increasing its dominance or not on that day. It is meant to be applied to altcoins on medium intervals. I put it together to test the following hypothesis: On days when BTC dominance is on the rise, altcoins are harder to take off, because Bitcoin is draining the lifeblood out of them, so caution is needed when opening trades.
Olive background means BTC dominance is rising on that day, purple that it is decreasing. White background means it is not moving significantly in any direction.
You can change the resolution (i.e. apply the DMI/ADX to a different BTC.D interval), just make sure to lower the threshold as well. I hope you find a good use for it! Beware if you try to incorporate it in your strategy, it uses higher timeframe data and hence is prone to repainting.