Spectra Sort

The grid's four corners are fixed. Drag the loose swatches and swap them until colour transitions cleanly across every row and column, corner to corner.

• Drag any non-anchor tile onto another to swap the two.
• Aim to reduce the smoothness error toward the ideal shown in the status bar.
• Solve in as few swaps and as quickly as you can for a higher score.
• Each solved board unlocks the next, larger level.

• Desktop: click and drag a swatch onto another to swap; click Daily, Practice, Blind, or Reset.
• Phone & tablet: drag swatches with your finger, fully touch-enabled.

• Daily: the same seeded board for everyone each day.
• Practice: a fresh random board on demand.
• Blind: some tiles hide their colour until you solve, for bonus points and extra difficulty.

• Fix the rows that connect two anchored corners first; they constrain everything between.
• Plan swaps to move two tiles toward their right homes at once instead of nudging one at a time.

Spectra Sort trains your eye for hue, value and gradient, sharpening the colour perception every artist relies on.

• Skills: colour perception, hue and value, gradients, visual discrimination
• Best for: all ages (budding artists and designers)
• For parents & teachers: trains a discerning eye for colour.

Arranging swatches so colour transitions cleanly across every row and column between fixed corners is a two-dimensional interpolation in a colour space.

Fixing the four corners is the original constraint.

Corners fixed in both directions means each cell has two demands on it at once, which is why the puzzle is not simply sorting. Colour is at least three-dimensional, so a smooth path between two colours is not unique — and the grid forces one consistent choice.

Spectra Sort is a perception puzzle that trains your eye for hue, value, and gradient. It is an original, free browser game built in-house.

A free, original browser game on PlayPendium. No download, no install.