Silly dream

Last night I dreamed that I was in a huge house, filled with friendly strangers.  We were all visiting the house for some reason. Some huge ghost-monsters had sneaked into the house and were trying to fool everyone with their human-like voices that they were actually people.  So, one of the strangers came out with an idea - before anyone opened a door, they should first call out a number.  The idea was that the humans would call out normal numbers, like 4 or 5, and the ghosts would call out numbers like pi and e.  In the dream it made perfect sense, but of course that is silly, because the ghosts would just call out normal numbers too if they were trying to fool people.  Then, the strangers and I got into an argument about calculus - whether a constant's anti-derivative necessarily describes a line or whether it can describe a disjoint piece-wise linear function with constant slope.  I have never had such a nerdy dream in all my life.