We had a geek-moment when C asked me how many candles I wanted on my cake. I suggested that 5 would be good, for 3+2 (since I was concerned 32 candles would burn down my house!). Then C said we could be really geeky and do it in binary. There was a quick pause while we determined that 100000 would be 32 in binary. "Perfect," I said. "Should we just light the one on the left, and leave the others un-lit?" He said we should, but upon further reflection I wanted more candles to blow out than just one. So we settled for putting all the lit candles in a row, using a contrasting color for the leftmost one to indicate that it was "on".