The serpentine system is a method employed in the organization of a competition

Competition

Competition is a contest between individuals, groups, animals, etc. for territory, a niche, or a location of resources. It arises whenever two and only two strive for a goal which cannot be shared. Competition occurs naturally between living organisms which co-exist in the same environment. For...

 to define the seeded teams and arrange them in pools. The n ranked teams that will be involved in the tournament

Tournament

A tournament is a competition involving a relatively large number of competitors, all participating in a sport or game. More specifically, the term may be used in either of two overlapping senses:...

 are distributed in m pools according to the following algorithm

Algorithm

In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...

:

Pool 1	Pool 2	...	Pool m-1	Pool m
1	2	...	m-1	m
2m	2m-1	...	m+2	m+1
2m+1	2m+2	...	3m-1	3m
...

For instance, 12 teams would be organized in four-team pools, according to the serpentine system, as follows:

Pool 1	Pool 2	Pool 3
1	2	3
6	5	4
7	8	9
12	11	10

To improve competitivity, this method is sometimes used in conjunction with the drawing of lots

Drawing straws

Drawing straws is a selection method that is used by a group to choose one member of the group to perform a task after none has volunteered for it...

method: the serpentine system is used only for some of the teams involved in a competition ("seeds"); the rest is distributed in pools following a drawing of lots.