The report explores how different tax rates on goods can be best structured in a computer model. The researchers found that when people's spending habits change with their income, optimal tax rates on goods tend to be higher for luxury items and lower for necessities. Tax evasion and administrative costs also play a role in determining these rates. Overall, the complexity of factors like tax evasion and externalities tends to make optimal tax rates more progressive, meaning they are higher for wealthier individuals. The study suggests that a one-size-fits-all approach to taxing goods may not be the most effective way to redistribute wealth.