 When we proceed one step further and compare (a) four linear elements to (b) one quartic element (p=4), then both discrete problems will have three DOF but the quartic approximation will be approximately 40-times more efficient.When performing few more steps like this, the reader will see that the efficiency gap opens extremely fast.On the contrary, small low-order elements can capture small-scale features such as singularities much better than large high-order ones.