Chord progressions involving the tonic, a chromatic mediant, and then the tonic: I-<span class="music-symbol" style="font-family: Arial Unicode MS, Lucida Sans Unicode;">♭</span>vi-I.
<a href="//commons.wikimedia.org/wiki/User:Hyacinth" title="User:Hyacinth">Hyacinth</a>
<span class="int-own-work" lang="en">Own work</span>