Triangles appear to reflect a balance of forces, causing a sideways movement that is usually associated with decreasing volume and volatility. Triangles contain five overlapping waves that subdivide 3-3-3-3-3 and are labeled a-b-c-d-e. A triangle is delineated by connecting the termination points of waves a and c, and b and d. Wave e can undershoot or overshoot the a-c line, and in fact, our experience tells us that it happens more often than not.

There are two varieties of triangles: contracting and expanding. Within the contracting variety, there are three types: symmetrical, ascending, and descending, as illustrated in Figure . There are no variations on the rarer expanding triangle. It always appears as depicted in Figure, which is why Elliott termed it a “reverse symmetrical” triangle.
Figure  depicts contracting triangles as taking place within the area of preceding price action, in what may be termed regular triangles. However, it is extremely common for wave b of a contracting triangle to exceed the start of wave a in what may be termed a running  triangle, as shown in Figure 1. Despite their sideways appearance, all triangles, including running triangles, effect a net retracement of the preceding wave at wave’s end.

Triangle
Examples Thereare several real life examples of triangles in the charts in this course. As you will notice, most of the subwaves in a triangle are zigzags, but sometimes one of the subwaves (usually wave c) is more complex than the others and can take the shape of a regular or expanded flat or multiple zigzag. In rare cases, one of the sub-waves (usually wave e) is itself a triangle, so that the entire pattern protracts into nine waves. Thus, triangles, like zigzags, occasionally display a development that is analogous to an extension. One example occurred in silver from 1973 through 1977.
Although upon extremely rare occasions a second wave in an impulse appears to take the form of a triangle, triangles nearly always occur in positions prior to the final actionary wave in the pattern of one larger degree, i.e., as wave four in an impulse, wave B in an A-B-C, or the final wave X in a double or triple zig-zag or combination.A triangle may also occur as the final actionary pattern in a corrective combination, although even then it always precedes the final actionary wave in the pattern of one larger degree than the corrective combination.
In the stock market, when a triangle occurs in the fourth wave position, wave five is sometimes swift and travels approximately the distance of the widest part of the triangle. Elliott used the word “thrust” in referring to this swift, short motive wave following a triangle. The thrust is usually an impulse but can be an ending diagonal. In powerful markets, there is no thrust, but instead a prolonged fifth wave. So if a fifth wave following a triangle pushes past a normal thrust measurement,it is signaling a likely protracted wave. Post-triangle advancing impulses in commodities at degrees above Intermediate are usually the longest wave in the sequence,
On the basis of our experience with triangles, as the example in Figure illustrates, we propose that often the time at which the boundary lines of a contracting triangle reach an apex coincides exactly with a turning point in the market. Perhaps the frequency of this occurrence would justify its inclusion among the guidelines associated with the Wave Principle.
The term “horizontal” as applied to triangles refers to these corrective triangles in general, as opposed to the term “diagonal”. Thus, the terms “horizontal triangle” and “diagonal triangle” denote these specific forms under the Wave Principle. The simpler terms “triangle” and “wedge” may be substituted, but keep in mind that technical chart readers have long used these terms to communicate less specifically subdivided forms defined only by overall shape. Having separate terms can be useful.
Corrective Combinations
Double and Triple Threes

Fig 1
Elliott called sideways combinations of corrective patterns “double threes” and “triple threes.” While a single three is any zigzag or flat, a triangle is an allowable final component of such combinations and in this context is called a “three.” A double or triple three, then, is a combination of simpler types of corrections, including the various types of zigzags, flats and triangles. Their occurrence appears to be the flat correction’s way of extending sideways action. As with double and triple zigzags, each simple corrective pattern is labeled W, Y and Z. The reactionary waves, labeled X, can take the shape of any corrective pattern but are most commonly zigzags.
Combination of threes were labeled differently by Elliott at different times, although the illustrative pattern always took the shape of two or three juxtaposed flats, as shown in Figures. However, the component patternsalways took the shape of two or three juxtaposed flats, as shown in Figures 1-45 and 1-46. However, the component patterns more commonly alternate in form. For example, a flat followed by a triangle is a more typical type of double three, as illustrated in Figure 1.
A flat followed by a zigzag is another example, as shown in Figure 1-48. Naturally, since the figures in this section depict corrections in bull markets, they need only be inverted to observe them as upward corrections in bear markets.
For the most part, double threes and triple threes are horizontal in character. Elliott indicated that the entire formations could slant against the larger trend, although we have never found this to be the case. One reason is that there never appears to be more than one zigzag in a combination. Neither is there more than one triangle. Recall that triangles occurring alone precede the final movement of a larger trend. Combinations appear to recognize this character and sport triangles only as the final wave in a double or triple three.