Maria's Performance Pizza is a small restaurant in Miami that sells gluten-free pizzas. Maria's very tiny kitchen has barely enough room for the four ovens in which her workers bake the pizzas. Maria signed a lease obligating her to pay the rent for the four ovens for the next year. Because of this, and because Maria's kitchen cannot fit more than four ovens, Maria cannot change the number of ovens she uses in her production of pizzas in the short run.
However, Maria's decision regarding how many workers to use can vary from week to week because her workers tend to be students. Each Monday, Maria lets them know how many workers she needs for each day of the week. In the short run, these workers are fixed/variable inputs, and the ovens are fixed/variable inputs