This paper was prompted by a question from the audience in a public lecture I gave at the Newcastle Centre for Life. I used the rather fabulous scintillating grid illusion (Schrauf, Lingelbach and Wist, 1994) as a "weird optical illusion" demo. A gentleman in the audience said ,"It doesn't scintillate so much if you cover one eye." I'd never noticed that, but did a quick show of hands, and sure enough most people seemed to agree. I had three local sixth-formers due to come to my lab to do science projects under the Nuffield summer bursary scheme, and I thought I'd have one of them look into this. Andrew Lucas went back to the Centre for Life and other public areas of Newcastle, and got people to rate the scintillations while wearing glasses which allowed them to see out of one or both eyes. He too got the same effect, which was interesting as it hadn't been reported in the existing literature. Before I published it, I wanted to collect more formal data, so I set up an experiment on a 3D monitor, which allowed me to interleave binocular and monocular images, without participants even noticing. Two undergraduates, Chris Smith and Joe Robson, ran these experiments as their third-year project. It was fun to run a project which had so many non-professional scientists contributing.