This script will paint 1 & 3 bars per 'The Strat'.
N.B. Per 'The Strat' a bar is seen as a 1 (inside) when the bar's high or low is an equal tick to the previous bar.
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.