Messinger's Law:
When ordering project supplies, regardless of the number of suppliers, said parts will be delivered in the reverse order of which they are needed for project completion (ie, part needed first arrives last, part needed last arrives first). The law can not be defeated by postponing the ordering of parts needed last. Parts needed first will find a way to avoid delivery until all other orders have been placed and deliveries made.
Adendum:
If insuficient storage space is available for parts needed last they will arrive ahead of schedule.