Utility companies generate three-phase electric power, which consists of three sinusoidal voltages with phase angles of 0 degrees, 120 degrees, and 240 degrees. The ac generators described in most introductory textbooks are single-phase generators, so physics students are not likely to learn about three-phase power. I have developed a simple way to display the waveforms of the three-phase power supplied to my lab and to demonstrate an interesting feature of three-phase power. The waveform displays require three small transformers, a Vernier Lab Pro[R] data-collection device, and a computer; but the demonstration requires only the transformers and some miniature light bulbs. I have also developed a way to demonstrate how six-phase ac can be derived from three-phase ac.