If you graph a linear function, you get a line. If you graph a quadratic function, you get something called a parabola. A parabola tends to look like a smile or a frown, depending on the function. Check out this tutorial and learn about parabolas!
Green Door Meanings. Green bursts with images of spring, and so green is symbolic of renewal, growth, rejuvenation and transformation. Green is associated with the earth, and can provide grounding energies. Green is also used in holistic healing practices because it promotes physical well-being as well as compassion.
In China, it's tradition to paint the front door red before the new year, to invite good luck and happiness. In Catholocism, the red door on a chapel symbolized the blood of christ, and other martyrs, to signify that the ground beyond the door (inside the church) was holy, and a sanctuary from physical and spiritual evils.