As young students, Dominic Kelly and his friends enjoyed watching ants
gather on pieces of sandwiches. Later, as a university student, Dominic
decided to study this with a more formal experiment. He chose three types of
sandwich fillings (vegemite, peanut butter, and ham \& pickles), four types
of bread (multigrain, rye, white, and wholemeal), and put butter on some of
the sandwiches. To conduct the experiment he randomly chose a sandwich,
broke off a piece, and left it on the ground near an ant hill. After
several minutes he placed a jar over the sandwich bit and counteed the
number of ants. He repeated the process, allowing time for ants to return to
the hill after each trial, until he had two samples for each combination of
the three factors.