On my website on  #visualperception , visual phenomena and #opticalillusion I have recently updated the “Benham Top” http://michaelbach.de/ot/col-Benham/ to a modern Flash-less version. That prompted me to think a little more about it. While historically this has been a spinning top, rotation is not really necessary, it's the spatio-temporal pattern that matters (doubtless this has occurred to many before me). So I “unrolled” the top and made a version without rotation: http://michaelbach.de/ot/col-Benham2/

    Interestingly, this easily shows that the pattern does not matter at all!