Diamond

The Diamond draws a rhombus touching the midpoint of each side of the box you define with two clicks. Its value is almost entirely about recognisability: the diamond is the universal flowchart symbol for a decision, so a diamond on a chart reads as "something is decided here" to anyone, without a legend and without explanation.

That matters because a chart carrying several rectangles quickly loses the ability to distinguish between them by anything other than colour, and colour is usually already carrying other meaning. A different silhouette gives you a second axis to communicate on, and the diamond stays distinguishable from a rectangle even at small sizes and in monochrome.

Because the rhombus is inscribed in the box rather than drawn from a centre and a radius, it stretches with the frame. A wide, shallow diamond marks a decision spanning several bars; a tall, narrow one marks a decision about a price level.

1. 1
   Select the Diamond tool

   Choose Diamond from the Shapes group in the drawing toolbar.
2. 2
   Click one corner

   Place the first point at one corner of the region the diamond should occupy.
3. 3
   Click the opposite corner

   Place the second point diagonally opposite. The rhombus fills the box between them.
4. 4
   Adjust

   Drag either handle to resize. Open the popup for colour, fill and line style.

• Decision points — the flowchart convention for a branch, used for exactly that on a chart: the bar where a plan splits into hold or exit, add or wait. Anyone who has read a flowchart understands it without a legend.
• Scheduled events — an announcement whose outcome is unknown but whose timing is not. A diamond communicates "something resolves here" better than a rectangle, which implies a zone.
• Conditional levels — a level that only matters if something else happens first. Mark the condition with a diamond and the consequence with a rectangle or arrow.
• Review markers — on a post-trade chart, mark the bars where a different decision was available. The diamond makes the branch explicit rather than implied.
• Distinguishing from zones — on a chart already carrying several rectangles, a diamond is instantly distinguishable at small sizes in a way another rectangle is not.

• 1.ISO 5807 — flowchart symbols — International Organization for Standardization
• 2.The Visual Display of Quantitative Information — Edward R. Tufte