Detecting candlestick pattern

I have a question about a simple box drawing algorithm done in a chart.

A box should be drawn over 3 certain candlesticks. The three candlesticks are classified like: the highs and lows of the left and right candlesticks are biggger/lower than the high and the low of the middle one. So the left and right candlestick cover the middle one.

If this pattern is detected, a rectangled (dashed) box should mark that pattern with top box of the highest high and the lowest low of the three candlesticks.

Thank you!