laws & principles
Gestalt: continuity
What is the Gestalt law of continuity?
Continuity is the eye's preference for smooth, unbroken paths. When lines or rows of elements cross or branch, you group the ones that carry on in the same direction, not the ones that merely happen to meet.
Also known as: law of continuity, good continuation, continuity principle
The demo
The dots make an X. Ask yourself: is it two straight lines crossing, or two bent corners meeting tip to tip? Switch the colouring and see which one your eye refuses to believe.
Two straight lines passing through each other - the reading your eye reaches for without being asked.
What this demo shows (text version)
Nine dots are arranged as an X - two diagonal lines that cross in the middle. Colouring them as two straight diagonals matches how almost everyone reads the figure: two continuous lines passing through one another.
The alternative colours the dots by their top and bottom halves instead, so the X becomes two angles meeting at their tips - a perfectly valid description that nonetheless feels wrong, because the eye insists on following the smooth, unbroken path. That insistence is the Gestalt law of continuity.
Where the two strands crossed, you did not see a corner - you saw each line run straight on through. The eye follows the gentlest path, which is why a stray dot on a curve feels part of it, and a sharp turn feels like a break.
Continuity is what makes a row of inputs, a timeline or a breadcrumb trail read as one connected thing: align elements along a line and the eye runs the length of it, binding them together. Break the alignment and the connection breaks with it.
It quietly steers which way people scan. Lead the line and you lead the gaze - off the end of a sentence into a call to action, or along a path of numbered steps - because the eye would always rather continue than stop.