Task: Koch curve







Python: l = 300

def setup():
    size(400, 400)
    background(0, 0, 255)
    stroke(255)
    
    translate(width / 2.0, height / 2.0)
    
    translate(-l / 2.0, l * sqrt(3) / 6.0)
    for i in range(4):
        kcurve(0, l)
        rotate(radians(120))
        translate(-l, 0)


def kcurve(x1, x2):
    s = (x2 - x1) / 3.0
    if s < 5:
        pushMatrix()
        translate(x1, 0)
        line(0, 0, s, 0)
        line(2 * s, 0, 3 * s, 0)
        translate(s, 0)
        rotate(radians(60))
        line(0, 0, s, 0)
        translate(s, 0)
        rotate(radians(-120))
        line(0, 0, s, 0)
        popMatrix()
        return

    pushMatrix()
    translate(x1, 0)
    kcurve(0, s)
    kcurve(2 * s, 3 * s)
    translate(s, 0)
    rotate(radians(60))
    kcurve(0, s)
    translate(s, 0)
    rotate(radians(-120))
    kcurve(0, s)
    popMatrix()


VB: option explicit


const pi180= 0.01745329251994329576923690768489 
const pi=3.1415926535897932384626433832795 
class turtle
   
   dim fso
   dim fn
   dim svg
   
   dim iang  
   dim ori   
   dim incr
   dim pdown
   dim clr
   dim x
   dim y

   public property let orient(n):ori = n*pi180 :end property
   public property let iangle(n):iang= n*pi180 :end property
   public sub pd() : pdown=true: end sub 
   public sub pu()  :pdown=FALSE :end sub 
   
   public sub rt(i)  
     ori=ori - i*iang:
     if ori<0 then ori = ori+pi*2
   end sub 
   public sub lt(i):  
     ori=(ori + i*iang) 
     if ori>(pi*2) then ori=ori-pi*2
   end sub
   
   public sub bw(l)
      x= x+ cos(ori+pi)*l*incr
      y= y+ sin(ori+pi)*l*incr
   end sub 
   
   public sub fw(l)
      dim x1,y1 
      x1=x + cos(ori)*l*incr
      y1=y + sin(ori)*l*incr
      if pdown then line x,y,x1,y1
      x=x1:y=y1
   end sub
   
   Private Sub Class_Initialize()  
      setlocale "us"  
      initsvg
      pdown=true
   end sub
   
   Private Sub Class_Terminate()   
      disply
   end sub
   
   private sub line (x,y,x1,y1)
      svg.WriteLine "<line x1=""" & x & """ y1= """& y & """ x2=""" & x1& """ y2=""" & y1 & """/>"
   end sub 

   private sub disply()
       dim shell
       svg.WriteLine "</svg></body></html>"
       svg.close
       Set shell = CreateObject("Shell.Application") 
       shell.ShellExecute fn,1,False
   end sub 

   private sub initsvg()
     dim scriptpath
     Set fso = CreateObject ("Scripting.Filesystemobject")
     ScriptPath= Left(WScript.ScriptFullName, InStrRev(WScript.ScriptFullName, "\"))
     fn=Scriptpath & "SIERP.HTML"
     Set svg = fso.CreateTextFile(fn,True)
     if SVG IS nothing then wscript.echo "Can
     svg.WriteLine "<!DOCTYPE html>" &vbcrlf & "<html>" &vbcrlf & "<head>"
     svg.writeline "<style>" & vbcrlf & "line {stroke:rgb(255,0,0);stroke-width:.5}" &vbcrlf &"</style>"
     svg.writeline "</head>"&vbcrlf & "<body>"
     svg.WriteLine "<svg xmlns=""http://www.w3.org/2000/svg"" width=""800"" height=""800"" viewBox=""0 0 800 800"">" 
   end sub 
end class

sub koch (n,le)
  if n=0 then x.fw le :exit sub
  koch n-1, le/3
  x.lt 1
  koch n-1, le/3
  x.rt 2
  koch n-1, le/3
  x.lt 1
  koch n-1, le/3
end sub

 dim x,i
set x=new turtle
x.iangle=60
x.orient=0
x.incr=3
x.x=100:x.y=300
for i=0 to 3
  koch 7,100
  x.rt 2
next  
set x=nothing