;;; The Bathroom Problem

;;; Some sims share a bathroom and need to use that bathroom either to
;;; wash their hands or to use the toilet.  Only one sim may use the
;;; toilet at any time, and for the sake of privacy, no other sims may
;;; be in the bathroom while a sim is using the toilet.  When no sims
;;; are using the toilet, any number of sims can concurrently be in the
;;; bathroom to wash their hands.  If there are sims using the toilet or
;;; washing their hands, no other sims may use the toilet no matter how
;;; urgent it is.