$ filename "t.exe"
'uses rt32
'uses rtl64
uses window

Window "TURTLE", 600, 600, 2
Font 12,24,0,"courier"
sys_mode=4
float a,b,x2,y2,angle=1,angle_difference=.8
sys counter,color_value=7,difference=2,length=500,x=50,y=550

ClsColor 200,200,248
y2 = y - length
length = length - difference
y = y2

While counter <180
      a = sin(rad(angle)) * length
      b = cos(rad(angle)) * length
      x2 = x + b
      y2 = y + a
      Line x, y, x2, y2, 1, color_value,color_value,color_value
      angle = angle + angle_difference
      length = length - difference
      a = sin(rad(angle)) * length
      b = cos(rad(angle)) * length
      x = x2 - a
      y = y2 + b
      Line x2, y2, x, y, 1, color_value,color_value,color_value
      angle = angle + angle_difference
      length = length - difference
      a = sin(rad(angle)) * length
      b = cos(rad(angle)) * length
      x2 = x - b
      y2 = y - a
      Line x, y, x2, y2, 1, color_value,color_value,color_value
      angle = angle + angle_difference
      length = length - difference
      a = sin(rad(angle)) * length
      b = cos(rad(angle)) * length
      x = x2 + a
      y = y2 - b
      Line x2, y2, x, y, 1, color_value,color_value,color_value
      length = length - difference
      angle = angle + angle_difference
      counter +=1
      color_value += Rand(4,8)
Wend
Pause
WinEnd