The article by Buff Dormeier in this issue, "Between Price And Volume," presents the volume price confirmation indicator (VPCI), which is an interesting indicator that combines price and volume action to produce reliable signals.
The coding for AmiBroker is straightforward and is shown here. Comments inside the code make it self-explanatory. The formula can be used as an indicator as well as a simple trading system. To use it, enter the code in Formula Editor and choose Tools: Apply Indicator and/or Tools: Backtest menu.