add structure for random symetric images

	r.HandleFunc("/green/?", greenHandler)

	r.HandleFunc("/blue/?", blueHandler)

	r.HandleFunc("/red/?", redHandler)

	r.HandleFunc("/grid/?", grid6X6Handler)

	r.HandleFunc("/grid/random/?", gridRandomHandler)

	r.HandleFunc("/grid/[0-8]?", gridColorHandler)

	r.HandleFunc("/grid/random/?", gridRandomHandler)

	r.HandleFunc("/grid/random/[0-8]/?", gridRandomColorHandler)

	r.HandleFunc("/grid/random/symetric?", gridRandomSymetricHandler)

	r.HandleFunc("/grid/random/symetric/[0-8]/?", gridRandomSymetricColorHandler)

	r.HandleFunc("/gradient/?", gradientHandler)

	r.AddStaticResource(root)

package main

import (

	"image"

	"image/color"

	"log"

	"net/http"

)

// handler for "/gird/random/symetric"

// generates a black and white grid random image.

func gridRandomSymetricHandler(w http.ResponseWriter, r *http.Request) {

	m := image.NewRGBA(image.Rect(0, 0, 240, 240))

	colorMap := MapOfColorPatterns()

	drawRandomSymetricGrid6X6(m, colorMap[0][0], colorMap[0][1])

	var img image.Image = m

	writeImage(w, &img)

}

// handler for "/grid/random/symetric[0-9]"

// generates a grid random image with a specific color based on the colorMap

func gridRandomSymetricColorHandler(w http.ResponseWriter, r *http.Request) {

	intID, err := PermalinkID(r, 3)

	if err != nil {

		log.Printf("error when extracting permalink id: %v", err)

	} else {

		m := image.NewRGBA(image.Rect(0, 0, 240, 240))

		colorMap := MapOfColorPatterns()

		drawRandomGrid6X6(m, colorMap[int(intID)][0], colorMap[int(intID)][1])

		var img image.Image = m

		writeImage(w, &img)

	}

}

// drawRandomGrid6X6 builds a grid image with with 2 colors selected at random for each quadrant.

func drawRandomSymetricGrid6X6(m *image.RGBA, color1, color2 color.RGBA) {

	size := m.Bounds().Size()

	quad := size.X / 6

	colorMap := make(map[int]color.RGBA)

	var currentQuadrand = 0

	for x := 0; x < size.X; x++ {

		if x/quad != currentQuadrand {

			// when x quadrant changes, clear map

			colorMap = make(map[int]color.RGBA)

			currentQuadrand = x / quad

		}

		for y := 0; y < size.Y; y++ {

			yQuadrant := y / quad

			if _, ok := colorMap[yQuadrant]; !ok {

				colorMap[yQuadrant] = getRandomColor(color1, color2)

			}

			m.Set(x, y, colorMap[yQuadrant])

		}

	}

}