Square Tetrad
Four colors evenly spaced at 90° intervals on the color wheel — maximum hue variety with perfect symmetry.
What it means
A square tetrad (formerly called "tetradic") uses four hues spaced exactly 90° apart, forming a square on the color wheel. Each adjacent pair is 90° apart, and each opposite pair is complementary (180°). This gives you two axes of contrast and four maximally distinct hues.
Square tetrads are the most symmetrical four-hue harmony. The equal spacing makes every pair visually distinct, but the energy is high — balance requires letting one or two hues dominate while the others support.
Why it matters in palette design
PerfectPalette supports Square Tetrad as a harmony mode in the editor. Square tetrad palettes are powerful for data visualization (four distinct categorical colors) and complex UIs (primary + secondary + accent + highlight). The challenge is controlling the energy — the 60-30-10 rule becomes more like 50-25-15-10 with four hues.
Common confusion
Square Tetrad vs. Rectangular Tetrad: Both use four hues forming two complementary pairs. The square form uses equal 90° spacing; the rectangular form uses unequal spacing (e.g., 60° and 120°). "Double complementary" is another name for the rectangular form. PerfectPalette offers both as separate harmony modes.
Example
A data dashboard uses four square tetrad hues for categorical chart series: blue (#3B82F6), orange (#F97316), green (#22C55E), and violet (#8B5CF6). The four hues are maximally distinct, making chart legends unambiguous. Blue dominates the UI chrome; the other three are reserved for data only.
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Apply this to your palette
Open PerfectPalette and put these concepts into practice with your own colors.