Rectangular Tetrad
Four colors forming two complementary pairs with unequal spacing — a rectangle on the color wheel, also known as double complementary.
What it means
A rectangular tetrad arranges four hues as two complementary pairs, but unlike the square tetrad, the spacing between adjacent hues is unequal. For example, hues at 0°, 60°, 180°, and 240° form a rectangle where adjacent hues are alternately 60° and 120° apart.
This asymmetry creates a natural warm/cool axis, making it easier to establish a dominant temperature. Rectangular tetrads feel less intense than square tetrads while still providing four distinct hues and two complementary pairs.
Why it matters in palette design
PerfectPalette supports Rectangular Tetrad as a harmony mode alongside Square Tetrad. The rectangular form is more common in real-world palettes because the unequal spacing naturally creates a dominant and subordinate axis — making balance easier to achieve than the fully symmetric square form.
Common confusion
Rectangular Tetrad vs. double complementary: They are the same concept — “double complementary” is an older name for what color theory now calls a rectangular tetrad. PerfectPalette uses “Rectangular Tetrad” as the mode name; “double complementary” appears only as an explanatory synonym.
Example
A travel website uses a rectangular tetrad: deep teal (#0D9488), warm coral (#F97066), gold (#EAB308), and indigo (#6366F1). Teal and coral are one complementary pair; gold and indigo form the other. Teal dominates the interface; coral highlights CTAs; gold and indigo accent section headers and badges.
Learn more
Apply this to your palette
Open PerfectPalette and put these concepts into practice with your own colors.