**OVERVIEW**

This indicator automatically draws bullish alternate bat harmonic patterns and price projections derived from the ranges that constitute the patterns.

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**CONCEPTS**

**Green and Red Candles**

• A green candle is one that closes with a close price equal to or above the price it opened.

• A red candle is one that closes with a close price that is lower than the price it opened.

**Swing Highs and Swing Lows**

• A swing high is a green candle or series of consecutive green candles followed by a single red candle to complete the swing and form the peak.

• A swing low is a red candle or series of consecutive red candles followed by a single green candle to complete the swing and form the trough.

**Peak and Trough Prices (Basic)**

• The peak price of a complete swing high is the high price of either the red candle that completes the swing high or the high price of the preceding green candle, depending on which is higher.

• The trough price of a complete swing low is the low price of either the green candle that completes the swing low or the low price of the preceding red candle, depending on which is lower.

**Historic Peaks and Troughs**

The current, or most recent, peak and trough occurrences are referred to as occurrence zero. Previous peak and trough occurrences are referred to as historic and ordered numerically from right to left, with the most recent historic peak and trough occurrences being occurrence one.

**Range**

The range is simply the difference between the current peak and current trough prices, generally expressed in terms of points or pips.

**Support and Resistance**

• Support refers to a price level where the demand for an asset is strong enough to prevent the price from falling further.

• Resistance refers to a price level where the supply of an asset is strong enough to prevent the price from rising further.

Support and resistance levels are important because they can help traders identify where the price of an asset might pause or reverse its direction, offering potential entry and exit points. For example, a trader might look to buy an asset when it approaches a support level , with the expectation that the price will bounce back up. Alternatively, a trader might look to sell an asset when it approaches a resistance level , with the expectation that the price will drop back down.

It's important to note that support and resistance levels are not always relevant, and the price of an asset can also break through these levels and continue moving in the same direction.

**Upper Trends**

• A return line uptrend is formed when the current peak price is higher than the preceding peak price.

• A downtrend is formed when the current peak price is lower than the preceding peak price.

• A double-top is formed when the current peak price is equal to the preceding peak price.

**Lower Trends**

• An uptrend is formed when the current trough price is higher than the preceding trough price.

• A return line downtrend is formed when the current trough price is lower than the preceding trough price.

• A double-bottom is formed when the current trough price is equal to the preceding trough price.

**Wave Cycles**

A wave cycle is here defined as a complete two-part move between a swing high and a swing low, or a swing low and a swing high. The first swing high or swing low will set the course for the sequence of wave cycles that follow; for example a chart that begins with a swing low will form its first complete wave cycle upon the formation of the first complete swing high and vice versa.

Figure 1.

**Fibonacci Retracement and Extension Ratios**

The Fibonacci sequence is a series of numbers in which each number is the sum of the two preceding numbers, starting with 0 and 1. For example 0 + 1 = 1, 1 + 1 = 2, 1 + 2 = 3, and so on. Ultimately, we could go on forever but the first few numbers in the sequence are as follows: 0 , 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144.

The extension ratios are calculated by dividing each number in the sequence by the number preceding it. For example 0/1 = 0, 1/1 = 1, 2/1 = 2, 3/2 = 1.5, 5/3 = 1.6666..., 8/5 = 1.6, 13/8 = 1.625, 21/13 = 1.6153..., 34/21 = 1.6190..., 55/34 = 1.6176..., 89/55 = 1.6181..., 144/89 = 1.6179..., and so on. The retracement ratios are calculated by inverting this process and dividing each number in the sequence by the number proceeding it. For example 0/1 = 0, 1/1 = 1, 1/2 = 0.5, 2/3 = 0.666..., 3/5 = 0.6, 5/8 = 0.625, 8/13 = 0.6153..., 13/21 = 0.6190..., 21/34 = 0.6176..., 34/55 = 0.6181..., 55/89 = 0.6179..., 89/144 = 0.6180..., and so on.

1.618 is considered to be the 'golden ratio', found in many natural phenomena such as the growth of seashells and the branching of trees. Some now speculate the universe oscillates at a frequency of 0,618 Hz, which could help to explain such phenomena, but this theory has yet to be proven.

Traders and analysts use Fibonacci retracement and extension indicators, consisting of horizontal lines representing different Fibonacci ratios, for identifying potential levels of support and resistance. Fibonacci ranges are typically drawn from left to right, with retracement levels representing ratios inside of the current range and extension levels representing ratios extended outside of the current range. If the current wave cycle ends on a swing low, the Fibonacci range is drawn from peak to trough. If the current wave cycle ends on a swing high the Fibonacci range is drawn from trough to peak.

**Harmonic Patterns**

The concept of harmonic patterns in trading was first introduced by H.M. Gartley in his book "Profits in the Stock Market", published in 1935. Gartley observed that markets have a tendency to move in repetitive patterns, and he identified several specific patterns that he believed could be used to predict future price movements.

Since then, many other traders and analysts have built upon Gartley's work and developed their own variations of harmonic patterns. One such contributor is Larry Pesavento, who developed his own methods for measuring harmonic patterns using Fibonacci ratios. Pesavento has written several books on the subject of harmonic patterns and Fibonacci ratios in trading. Another notable contributor to harmonic patterns is Scott Carney, who developed his own approach to harmonic trading in the late 1990s and also popularised the use of Fibonacci ratios to measure harmonic patterns. Carney expanded on Gartley's work and also introduced several new harmonic patterns, such as the Shark pattern and the 5-0 pattern.

The bullish and bearish Gartley patterns are the oldest recognized harmonic patterns in trading and all the other harmonic patterns are ultimately modifications of the original Gartley patterns. Gartley patterns are fundamentally composed of 5 points, or 4 waves.

**Bullish and Bearish Alternate Bat Patterns**

• Bullish alternate bat patterns are fundamentally composed of three troughs and two peaks. The second peak being lower than the first peak and the second trough being higher than the first, with the third trough being lower than both the first and second troughs.

• Bearish alternate bat patterns are fundamentally composed of three peaks and two troughs. The second trough being higher than the first trough and the second peak being lower than the first, with the third peak being higher than both the first and second peaks.

The ratio measurements recommended by Scott Carney, who originated the pattern, are as follows:

• Wave 1 of the pattern, generally referred to as XA, has no specific ratio requirements.

• Wave 2 of the pattern, generally referred to as AB, should retrace to 38.2% of the range set by wave 1.

• Wave 3 of the pattern, generally referred to as BC, should retrace by at least 38.2%, but no further than 88.6% of the range set by wave 2.

• Wave 4 of the pattern, generally referred to as CD, should extend to at least 200%, but no further than 361.8% of the range set by wave 3.

• The last measure, generally referred to as AD, is that of wave 4 as a ratio of the range set by wave 1, which should extend to 113%.

**Measurement Tolerances**

In general, tolerance in measurements refers to the allowable variation or deviation from a specific value or dimension. It is the range within which a particular measurement is considered to be acceptable or accurate. In this script I have applied this concept to the measurement of harmonic pattern ratios to increase to the frequency of pattern occurrences.

For example, the AB measurement of Gartley patterns is generally set at around 61.8%, but with such specificity in the measuring requirements the patterns are very rare. We can increase the frequency of pattern occurrences by setting a tolerance. A tolerance of 10% to both downside and upside, which is the default setting for all tolerances, means we would have a tolerable measurement range between 51.8-71.8%, thus increasing the frequency of occurrence.

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**FEATURES**

**Inputs**

• AB Lower Tolerance

• AB Upper Tolerance

• BC Lower Tolerance

• BC Upper Tolerance

• CD Lower Tolerance

• CD Upper Tolerance

• AD Lower Tolerance

• AD Upper Tolerance

• Pattern Color

• Label Color

• Show Projections

• Extend Current Projection Lines

**Alerts**

Users can set alerts for when the patterns occur.

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**LIMITATIONS**

All green and red candle calculations are based on differences between open and close prices, as such I have made no attempt to account for green candles that gap lower and close below the close price of the preceding candle, or red candles that gap higher and close above the close price of the preceding candle. This may cause some unexpected behaviour on some markets and timeframes. I can only recommend using 24-hour markets, if and where possible, as there are far fewer gaps and, generally, more data to work with.

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**NOTES**

A link to Scott's harmonic patterns webpage for anyone who may be interested: harmonictrader.com/harmonic-patterns/

Corrected logic that was previously drawing bearish patterns. Please be advised that at the time of writing Scott Carney's Harmonic Patterns webpage is incorrectly showing bullish patterns as bearish patterns and vice versa. This will be changed in due course according to Scott, as will the description of this script. To confirm, all bullish harmonic patterns are M shapes and all bearish harmonic patterns are W shapes. Apologies for any confusion this may have caused.