def flower(t, n, rf, re):
angle = asin(0.5 * float(rf) / re) * 180 / pi
rt(t, angle)
for _ in range(n):
arc(t, re, angle * 2)
lt(t, 180 - angle * 2)
arc(t, re, angle * 2)
lt(t, 180 - angle * 2 + 360 / n)
def pie(t, sides, radius):
angle1 = 360.0 / sides
angle2 = (180.0 - angle1) / 2
print angle1
print angle2
rt(t, angle1 / 2)
for _ in range(sides):
fd(t, radius)
lt(t, 180 - angle2)
fd(t, 2 * radius * sin(pi / 180 * angle1 / 2))
lt(t, 180 - angle2)
fd(t, radius)
rt(t, 180)
def arc(t, r, angle):
"""Draws an arc with the given radius and angle.
t: Turtle
r: radius
angle: angle subtended by the arc, in degrees
"""
arc_length = 2 * math.pi * r * abs(angle) / 360
n = int(arc_length / 4) + 1
step_length = arc_length / n
step_angle = float(angle) / n
# making a slight left turn before starting reduces
# the error caused by the linear approximation of the arc
lt(t, step_angle/2)
polyline(t, n, step_length, step_angle)
rt(t, step_angle/2)
def isosceles(t, r, angle):
"""Draws an icosceles triangle.
The turtle starts and ends at the peak, facing the middle of the base.
t: Turtle
r: length of the equal legs
angle: peak angle in degrees
"""
y = r * math.sin(angle * math.pi / 180)
rt(t, angle)
fd(t, r)
lt(t, 90+angle)
fd(t, 2*y)
lt(t, 90+angle)
fd(t, r)
lt(t, 180-angle)
