Ten magnetic stars where rotational period variations have been detected shown on the HR diagram. Those showing a long-term increase in rotation period are represented in blue (decelerating), those with a decrease in green (accelerating), and those transitioning from an increase to a decrease (or vice versa) in red (oscillating). The solid curves represent the results of evolution calculations of nonrotating, nonmagnetic stars. Models with ZAMS masses from 1.5 to 5 M_⊙ are shown at intervals of 0.1 M_⊙, while models with ZAMS masses from 5.5 to 9.5 M_⊙ are shown at intervals of 0.5 M_⊙. The numbers displayed next to the solid curves represent the ZAMS mass. To indicate the ages, points were placed at ten equal divisions of the period from ZAMS to TAMS.