Make your own Zöllner image

Move every slider. The measured values update beside the image. Download the result as a PNG.

Measured from the image

Sliders

Things to try

Set the hatch slant to zero. Watch the lean disappear while the lines stay put.
Raise the slant a few steps at a time. Note where the lean starts for you.
Change the hatch spacing and stroke length. Compare a sparse pattern with a dense one.

At the default settings this image measures 520 by 350 px. The sweep on the Zöllner page tracks Hatch slant from vertical (degrees); 0 removes the illusion and marks these values as weak: 0 to 20 deg.

Slider ranges

Setting	Min	Default	Max
Number of long lines	2	4	8
Distance between long lines (px)	40	70	120
Hatch slant from vertical (degrees); 0 removes the illusion	0	30	60
Hatch stroke length (px)	10	28	50
Distance between hatch strokes along a line (px)	8	16	40
Image width (px)	300	520	900

Your PNG carries a small bharamind.com credit strip under the image. Entertainment only. Not a vision or health test.