Perspective (graphical) towards the opposite vanishing point. Two-point perspective exists when the painting plate is parallel to a Cartesian scene in one axis (usually the z-axis) but not to the other two axes. If the scene being viewed consists solely of a cylinder sitting on a horizontal plane, no difference exists in the image of the cylinder between a one-point and two-point perspective. Two-point perspective has one set of lines parallel to the picture plane and two sets oblique to it. Parallel lines oblique to the picture plane converge to a vanishing point, which means that this set-up will require two vanishing
Tricritical point more components. It can be shown that three is the "minimum" number of components for which these points can appear. In this case, one may have a two-dimensional region of three-phase coexistence ("F" = 2-3+3 =2) (thus, each point in this region corresponds to a triple point). This region (F=2, P=3) will terminate in two critical lines of two-phase coexistence; these two critical lines (F=1, P=2) may then terminate at a single tricritical point. This point (F=0, P=1) is therefore "twice critical", since it belongs to two critical branches.<br> Indeed, its critical behavior is different from that of a conventional