study("Boring Candle", overlay=true)
candleColor = ( abs(open-close)/abs( high-low ) > 0.5 )? (open < close ? green : red) : blue
plotcandle(open, high, low, close, color = candleColor)
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.