Consider the following ideal gas engine cycle with only three steps: {12} –  isothermal compression at T-from V₁ to V₂ ; {23} – isobaric (constant pressure) heating T_- from T₊ to , where T₊ is chosen so that the volume increases back to ; {31} – isometric cooling from T₊ back to T_- , which returns the system to . Sketch this system's path in the pV- and ST-planes. Discuss problems with implementing this cycle reversibly.