class RecursiveCircle
  attr_accessor :box_length,:circle,:direction
  def initialize(n)
    @box_length = n
    @circle=[]
    (@box_length+1).times do 
      @circle.push Array.new(@box_length+1," ")
    end
    @direction="r"
  end
  def draw()
    fill(0,0,0,0,@direction)
    @circle.reverse.each do |row| 
      row.each do |col|
        print col
      end
      puts ""
    end
  end
  def fill(top_offset,right_offset,bottom_offset,left_offset,direction)
    return if top_offset > @box_length/2
    if(direction=="r")
      row_index= @box_length - bottom_offset
      col_index= left_offset
      col_index.upto(@box_length -right_offset) do
        @circle[row_index][col_index]="*"
        col_index=col_index+1
      end
      fill(top_offset+1,right_offset,bottom_offset+1,left_offset,"u")
    elsif(direction=="u")
      col_index = @box_length - right_offset
      row_index = @box_length - bottom_offset
      row_index.downto(top_offset) do
        @circle[row_index][col_index]="*"
        row_index=row_index-1
      end
      fill(top_offset,right_offset+1,bottom_offset,left_offset+1,"l")
    elsif(direction=="l")
      row_index= top_offset
      col_index= @box_length - right_offset
      col_index.downto(left_offset) do
        @circle[row_index][col_index]="*"
        col_index =col_index-1
      end
      fill(top_offset+1,right_offset,bottom_offset+1,left_offset,"d")
    elsif(direction=="d")
      col_index = left_offset
      row_index = top_offset
      row_index.upto(@box_length-bottom_offset) do  
        @circle[row_index][col_index]="*"
        row_index = row_index +1
      end
      fill(top_offset,right_offset+1,bottom_offset,left_offset+1,"r")
    end
  end
end
# เวลาเอาไปใช้ก็
x = RecursiveCircle(5)
x.draw

#!/usr/bin/python
 
from numpy import *
 
def snail(n):
	if n < 3 : raise ValueError, 'snail(n) : n must greater be than 3'
	sn = ones((n,n))
	sn[1,:n-1] = 0
	for i in range(1,n-2) :
		if i%4 == 0 :
			sn[i/2+1,i/2-1:i/2-1+(n-i)] = 0
		elif i%4 == 1 :
			sn[(i+1)/2:(i+1)/2+(n-i-1),n-(i+3)/2] = 0
		elif i%4 == 2 :
			sn[n-i/2-1,i/2:i/2+(n-i)] = 0
		else :
			sn[(i+3)/2:(i+3)/2+(n-i-1),(i-1)/2] = 0
	if n%2 == 0 : sn[n/2,n/2-1] = 0
	snstr = ''
	for i,j  in zip(sn.reshape(n**2),range(n**2)):
		if j%n == 0 : snstr += '\n'
		if i == 1 : snstr += '*'
		else : snstr += ' '
	return snstr
 
print snail(32)

>
#!/usr/bin/python
 
# This is our hero!
class snail():
 
    def __init__(self):
        self.trace = ''
        self.travelledDistance = 0
 
    def walk(self, distance, direction):
        # check input
        if distance == 0:
            self.trace = self.trace + 'x'   # if there's no distance, do eat
        elif distance < 0:
            return
        # always use lowercase
        direction = direction.lower()
        if direction == 'up':
            self.trace = self.trace + 'u' * distance
        elif direction == 'down':
            self.trace = self.trace + 'd' * distance
        elif direction == 'left':
            self.trace = self.trace + 'l' * distance
        elif direction == 'right':
            self.trace = self.trace + 'r' * distance
        else:
            return
        self.travelledLen = self.travelledDistance + distance
 
    def doHelix(self, distance, dir = ['right', 'down', 'left', 'up']):
        if distance < 0:
            return
        compass = 0
        self.walk(distance, dir[compass % 4])
        compass = compass + 1
        for step in range(distance, -1, -2):
            self.walk(step, dir[compass % 4])
            compass = compass + 1
            self.walk(step, dir[compass % 4])
            compass = compass + 1
</blockcode>
 
แล้วจากนั้นก็เอา path ที่ได้ไป plot โดยเริ่มจากจุด 0,0 ถ้าหากหอยเดินตกขอบที่กำหนดเราไม่สนใจ
 
<blockcode [type="python"]>
# Plot the trace in n*n sheet
def plot(trace, n):
    sheet = {}
 
    # Firstly, observe the trace and plot
    i = 0
    j = 0
    for step in range(0, len(trace)):
        if trace[step] == 'u':
            sheet[(i, j)] = step + 1
            i = i - 1
        elif trace[step] == 'd':
            sheet[(i, j)] = step + 1
            i = i + 1
        elif trace[step] == 'l':
            sheet[(i, j)] = step + 1
            j = j - 1
        elif trace[step] == 'r':
            sheet[(i, j)] = step + 1
            j = j + 1
        elif trace[step] == 'x': 
            sheet[(i, j)] = step + 1
 
    # Secondly, print the plot
    for i in range(0, n):
        for j in range(0, n):
            if sheet.has_key((i, j)):
                print '*',
            else:
                print ' ',
        print ''
</blockcode>
 
ลองพล็อตดูโดยเรียกใช้ตามนี้
 
<blockcode [type="python"]>
for n in range(0, 6):
    s = snail.snail()
    s.doHelix(n)
    s.trace
    snail.plot(s.trace, n + 1)
</blockcode>
 
ก็จะได้
 
<blockcode>
'xxx'
* 
'rdl'
* * 
  * 
'rrddllxx'
* * * 
    * 
* * * 
'rrrdddlllur'
* * * * 
      * 
*     * 
* * * * 
'rrrrddddlllluurrxx'
* * * * * 
        * 
* * *   * 
*       * 
* * * * * 
'rrrrrdddddllllluuurrrdl'
* * * * * * 
          * 
* * * *   * 
*     *   * 
*         * 
* * * * * * 
</blockcode>
 
code ยาวแฮะ ไม่เหมาะกับเขียนในห้องสอบอย่างแรง