Make your own Müller-Lyer 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 fin length to zero. Confirm both lines look equal.
Raise the fin length step by step. Note where the difference becomes obvious to you.
Change the fin angle with the fin length fixed. Compare sharp fins with wide ones.

At the default settings this image measures 368 by 250 px. The sweep on the Müller-Lyer page tracks Fin length (px); 0 removes the fins and the illusion and marks these values as weak: 0 to 30 px.

Slider ranges

Setting	Min	Default	Max
Shaft length (px), identical for both lines	100	240	400
Fin length (px); 0 removes the fins and the illusion	0	50	100
Fin angle from the shaft (degrees)	10	30	60
Line thickness (px)	1	3	8

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