Rabbi Sol: Strobe effect--Strobe Lights are lights that flash on and off extremely quickly, causing a stop action visual effect. They are used in photography and at rock concerts, amongst other uses. Strobe lighting has occasionally been blamed for causing epileptic seizures, and this was my allusion. Whilst dancing and clapping the lights under clapper control would wildly go on and off creating a strobe effect. A feeble joke on my part. And thank you for your answers to my questions. I once asked a cantor (of a Conservative congregation) about the cell phone. He demurred on that one, suggesting I ask a a Rabbi...I now have.