Straight lines.
Using a triple point phase diagram or "line graph chart" with temperature and pressure on the outsides then draw the reaction.
The related link below illustrates 3 ways of drawing a curve. The techniques are easily adapted to a quadratic curve.
Nobody knows mabey you will know some day great warrior.
This is a weird answer, but, maybe a lamp, a vase, a ball, a bowl, drinking glass, etc. I think you can think up more from that.