What was the purpose of the punnett square

The diagram is used by biologists to determine the probability of an offspring having a particular genotype

Predict genotypes

Explanation:

Punnett square is a diagram in which you can predict the possible genotype crossover from some alleles.

Was named after Reginald Punnet and biologist uses to tabulate a crossing of maternal and paternal alleles.

You choose your gene with it's dominant (capital letter) and recessive (lowercase letter) alleles and arrange them on the square before doing the breeding experiment.