This podclass tackles the heresies of the third century including Sabellius (founder of Modalism), Paul of Samosata (forerunner of the Adoptionist heresy), Manes (founder of Manichaeism that temporarily ensnared St. Augustine early on in his conversion) and  finally we consider two semi-heretics, Tertullian and Origin.   On the blog that has photos, you can see Tertullian above.  Below is Man-E-Faces, a good symbol of the Sabellian or Modalist heresy.  The third century heresies as outline by St. Alphonsus Liguori in the 18th century can be found on this link.