Chris and I were sitting in the living room when Douglas jumped into the room and announced that yellow and blue make green. Chris wondered what brought on the declaration of that fact. I started to sing a song they know about colors in case that was the root of the statement. I forgot that I had just cleaned the toilet a half an hour earlier and left the cleaner which is blue to sit in the water. Chris then asked Douglas if he just went to the bathroom and he had. Yes, yellow and blue do make green.