The surface of the Affymetrix array is like a giant checkerboard, and each square holds one unique type of probe. Using the music analogy, one square would hold millions of "Oh say can you see" probes, and the square next to it would hold millions of "rocket's red glare probes." Affymetrix builds these probes using the same type of manufacturing technology that is used to build microprocessors. Each probe is built one layer at a time, one base stacked on top of another, like checkers, until a full length probe is created, but thousands or millions of probes are synthesized simultaneously.

The FoodExpert-ID Array is about the size of a thumbnail, with about 97,000 squares, called "features". It represents genes from 33 different species and each feature is about 26 microns across. By way of comparison, a human hair is about 50 microns wide. For our example, we are just going to look at one corner, or a single feature, of an imaginary array. Normally, each probe is 17 bases long, but for purposes of illustration here, let's abbreviate this standard probe length and say that the probe is designed to be only a 6 base sequence, ATCATG. This probe is designed to detect goose DNA, and goose DNA only.