Wave Drift

What is happening

Like Drifting Tiles, this is a completely static image. But instead of a zigzag drift, the whole grid seems to ripple in one direction, like a wave.

Pressing “Reveal the answer” leaves only the middle row. Once the other rows disappear, so does the ripple.

Why it looks that way

The trick uses the same luminance sequence as Drifting Tiles: black → mid-tone → white → a different mid-tone. What changes is how the rows relate to each other.

• Every row keeps the same color order, so in peripheral vision all of them appear to drift in the same direction
• The horizontal offset grows a little with each row down the grid, so the “phase” of that drift shifts diagonally from top to bottom
• The result reads not as individual tiles moving, but as one continuous wave sweeping across the whole image

Because Drifting Tiles reverses every other row, it reads as a zigzag. Here every row points the same way, so it is perceived as a single large wave instead.

What changes the effect

• A larger per-row offset makes the wave look like a steep diagonal stripe; a smaller one makes it a gentle, slow wave
• More rows make the wave read across a wider area
• Tiles that are too large get processed by central vision, and the motion disappears

First described

After Jacques Faubert / Andrew Herbert, 1999
Source: "The peripheral drift illusion: A motion illusion in the visual periphery", Perception

The same effect family (peripheral drift) as [Drifting Tiles](/en/illusions/drifting-tiles/), with only the row phase changed.

See it in the timeline