In 1973 crude oil sold for $12 per barrel and the U.S. economy consumed 17 million barrels a day. That year OPEC cut off oil exports to the United States for six months, which we can read as a shift of the supply curve to the left from S₀ to S₁. Both panels start from the same equilibrium E₀ (17, 12) and show the identical shift.
The demand curves differ. In (a) demand is inelastic, as it is in the short run when people cannot quickly change how much oil they use, so the new equilibrium E₁ has a much higher price, $25, and only a slightly smaller quantity, 16. In (b) demand is elastic, as it is in the long run when cars, furnaces and habits can change, so E₁ has only a small rise in price, to $14, and a larger fall in quantity, to 13. The slider changes the size of the supply cut.