A Punnett Square is a diagram that we can use to predict the outcome of offspring with difference traits. It was named after Reginald Punnett who created this method to cross the parents allele pairs to find the genotypes of their offspring. A Punnett Square is a 4-square box and along the top is one of the parents genes, and along the left side, is the other parents genes. To get your outcomes you cross through the box, matching up along the lines to find the genotypes.