Step 1. Draw a supply curve for pizza and pick a quantity, Q₀. A vertical line up from Q₀ to the supply curve shows the price the firm chooses, P₀.
Step 2. Why that price? Think of it as two parts: the cost of production at the margin (ingredients, the oven, rent, wages) plus the firm's desired profit. Added together they give the price the firm wishes to charge, so Q₀ and P₀ are one point on the firm's supply curve.
Step 3. Now suppose the cost of production rises, say cheese by $0.75 per pizza. The firm wants to raise its price by that same amount, so the new point sits directly above the old one, $0.75 higher, at P₁.
Step 4. Shift the supply curve through that point. An increase in cost causes an upward (or leftward) shift of supply, from S to S': at any price the quantity supplied is smaller. Use the display options to step through the four figures, and the sliders to change the cost increase or the desired profit.