Request #374 From Jen

Kia ora (hello) from Aotearoa (New Zealand) I’m 43 and grew up in America. I remember reading a book that I thought for years was Asimov but can’t find it. It’s about a group of teens (I think) who are put in this white room with stairs & platforms and a toilet that continuously flushes. I think they drink from that source?? they figure out they need to dance to get food pellets. I think flashing colored lights were used at some stage to signal them to dance?? there’s a bizarre ending and I think one or two of them are suddenly back in the real world thinking it was all a dream but then they see traffic lights.  I’m pretty sure the last line is “without hesitation, they began to dance.”