Law of Continuity

The eye follows a smooth line or path and prefers continuous shapes over broken ones.

How to apply it

Put related items along one clear line, and let content run past the edge to show there is more.

Where Law of Continuity comes from

Continuity, often called good continuation, is one of the Gestalt principles of grouping. Gestalt psychologists, including Max Wertheimer in a 1923 paper on how people organise what they see, described how we group elements that lie along a line or curve and tend to follow a smooth path instead of a sudden turn. It sits alongside proximity, similarity and closure.

How to apply Law of Continuity, step by step

Put items that belong to one sequence on one clear line: a row, a column or a curve.
Keep the spacing and alignment along that line even, so the path reads as one.
To show there is more, let the next item run past the edge of the screen, with enough of it visible to read as a card.
Join steps that belong together with a line or connector, as in a stepper or a timeline.
Check where the line leads. The eye follows it, so end it on the primary action or the next step.

Law of Continuity in practice: a concrete example

The card row that hints it scrolls

A carousel with every card neatly inside the screen looks finished, so people do not try to swipe it. Let the last card run off the edge and the eye follows the line of cards past the screen, which tells people there is more without an arrow or a label. Many mobile apps use this peek for exactly that reason. The same idea makes the line in a stepper, a timeline or a breadcrumb read as one path.

Common Law of Continuity mistakes

Making every card fit exactly, so nothing hints that the row scrolls.
Breaking the line: items on one path that jump up and down, so the eye loses the trail.
Pointing a line or arrow at the wrong thing, so the eye follows it somewhere that does not matter.
Cutting the last item so little of it shows that it looks like a layout bug instead of a hint.

When Law of Continuity doesn't apply

When items should read as separate choices, a continuous line can join them by mistake. A row of unrelated settings, or fields that must be read one at a time, are clearer with clear breaks. And do not rely on a cut-off hint alone for important content: people using a mouse cannot swipe, so give them an arrow too.

How to tell you got it right

Look at the screen with your eyes half closed. Can you see the lines the eye will follow, and do they lead somewhere useful? Then watch someone use the row: do they try to swipe it without being told?

Law of Continuity: common questions

What is the law of continuity?

The eye prefers to follow a smooth line or path, so elements arranged along a line are seen as related, and the line is followed past the point where it seems to end.

What is an example of the law of continuity in UI?

A carousel whose last card is cut off at the edge, a stepper or timeline joined by a line, and a navigation bar whose items sit on one aligned line.

What is the difference between continuity and proximity?

Proximity groups items by how close they are. Continuity groups them by the line they sit on: items along one path read as a sequence, even when the gaps between them are large.

Why do carousels cut off the last item?

The cut-off card continues the line of cards past the edge of the screen. That tells people there is more to see and invites a swipe, without an arrow or a label.

Is the law of continuity the same as good continuation?

Yes. Good continuation is the older Gestalt name for the same idea.

Practise it on a real challenge

Streaming App — the row that never gets swiped

A streaming app's Trending row fits three cards exactly on the screen. Analytics show almost nobody swipes it, so the other eight titles go unseen.