You can change the slopes of the demand and supply curves as well as the amount of the
excise tax.
Initially you will see only the consumer (yellow) and producer (cyan) surplus. After you impose a tax some of those surpluses are appropriated by the taxing authority in an amount equal to the gray strip. But by driving a wedge between how the good is valued and the price paid, the tax results in a deadweight loss in an amount equal to the magenta triangle.