Are these lines really straight?


This is a great version of an old illusion – I came across it as the Edinburgh International Science Festival – amazing to think that these lines are actually straight…..


12 comments on “Are these lines really straight?

  1. Martha says:

    Good one! I had to put a piece of paper up by the screen to check. BTW, those questions about your video were blimmin’ impossible!

    • Martha says:

      Actually none of the lines are straight. They’ve all got knobbly bits at the corners. Odd that no one’s noticed that yet

  2. Anon says:

    They look gay to me

  3. Scrolling up and down is also very nice.

  4. Ian says:

    That’s an excellent illusion, thanks, Richard; perhaps the best version of that particular illusion I’ve seen. The image seems to move when scrolling up and down, too (noticed it as I was scrolling to comment here). As always, thanks for these delightful illusions and snippets of food for thought 🙂

  5. gail says:

    yes very cool

  6. could you invert this particular illusion?

    ie, have wavy lines, and then munge the corners so that they appear as straight – or is that getting too tricky for our visual cortex’s instinct to cope with?

  7. I wonder if there is some process which detects that something is going wrong, even though it is not clear what – the picture is not comfortable to look at, it has a certain “dissonance”. Although, given that it “moves” when you tilt your head, that may be enough to account for the feeling (micro movement of the head).

  8. lamanga2004 says:

    All lines straight?

    Maybe a better question would be: all shapes similarly oriented?

  9. Anonymous says:

    Maybe they could make non straight lines look straight.

  10. Stuart says:

    Save as and zoom in, and it’s clear that it’s a regular checkerboard with mini-checkerboards at 45 degrees. It would be interesting to know the optimum ratio between the sizes of the big and small squares for the best effect, is this it?

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