There's an indicator called Hourly High Low which is very useful indicator. I would like to see 4H High Low and perhaps 30M High Low which can be used in lower timeframes e.g. 1/5/15 min.
I looked at the source code for Hourly High Low  indicator and unfortunately I have no idea how to tweak it to construct 4H High Low or 30M High Low.

Can anyone accomplish this?