1 files changed, 0 insertions, 113 deletions
diff --git a/Demo/turtle/tdemo_planet_and_moon.py b/Demo/turtle/tdemo_planet_and_moon.py
deleted file mode 100644
index 14c4bbc..0000000
--- a/Demo/turtle/tdemo_planet_and_moon.py
+++ /dev/null
@@ -1,113 +0,0 @@
-#!/usr/bin/env python3
-"""       turtle-example-suite:
-
-        tdemo_planets_and_moon.py
-
-Gravitational system simulation using the
-approximation method from Feynman-lectures,
-p.9-8, using turtlegraphics.
-
-Example: heavy central body, light planet,
-very light moon!
-Planet has a circular orbit, moon a stable
-orbit around the planet.
-
-You can hold the movement temporarily by pressing
-the left mouse button with mouse over the
-scrollbar of the canvas.
-
-"""
-from turtle import Shape, Turtle, mainloop, Vec2D as Vec
-from time import sleep
-
-G = 8
-
-class GravSys(object):
-    def __init__(self):
-        self.planets = []
-        self.t = 0
-        self.dt = 0.01
-    def init(self):
-        for p in self.planets:
-            p.init()
-    def start(self):
-        for i in range(10000):
-            self.t += self.dt
-            for p in self.planets:
-                p.step()
-
-class Star(Turtle):
-    def __init__(self, m, x, v, gravSys, shape):
-        Turtle.__init__(self, shape=shape)
-        self.penup()
-        self.m = m
-        self.setpos(x)
-        self.v = v
-        gravSys.planets.append(self)
-        self.gravSys = gravSys
-        self.resizemode("user")
-        self.pendown()
-    def init(self):
-        dt = self.gravSys.dt
-        self.a = self.acc()
-        self.v = self.v + 0.5*dt*self.a
-    def acc(self):
-        a = Vec(0,0)
-        for planet in self.gravSys.planets:
-            if planet != self:
-                v = planet.pos()-self.pos()
-                a += (G*planet.m/abs(v)**3)*v
-        return a
-    def step(self):
-        dt = self.gravSys.dt
-        self.setpos(self.pos() + dt*self.v)
-        if self.gravSys.planets.index(self) != 0:
-            self.setheading(self.towards(self.gravSys.planets[0]))
-        self.a = self.acc()
-        self.v = self.v + dt*self.a
-
-## create compound yellow/blue turtleshape for planets
-
-def main():
-    s = Turtle()
-    s.reset()
-    s.getscreen().tracer(0,0)
-    s.ht()
-    s.pu()
-    s.fd(6)
-    s.lt(90)
-    s.begin_poly()
-    s.circle(6, 180)
-    s.end_poly()
-    m1 = s.get_poly()
-    s.begin_poly()
-    s.circle(6,180)
-    s.end_poly()
-    m2 = s.get_poly()
-
-    planetshape = Shape("compound")
-    planetshape.addcomponent(m1,"orange")
-    planetshape.addcomponent(m2,"blue")
-    s.getscreen().register_shape("planet", planetshape)
-    s.getscreen().tracer(1,0)
-
-    ## setup gravitational system
-    gs = GravSys()
-    sun = Star(1000000, Vec(0,0), Vec(0,-2.5), gs, "circle")
-    sun.color("yellow")
-    sun.shapesize(1.8)
-    sun.pu()
-    earth = Star(12500, Vec(210,0), Vec(0,195), gs, "planet")
-    earth.pencolor("green")
-    earth.shapesize(0.8)
-    moon = Star(1, Vec(220,0), Vec(0,295), gs, "planet")
-    moon.pencolor("blue")
-    moon.shapesize(0.5)
-    gs.init()
-    gs.start()
-    return "Done!"
-
-if __name__ == '__main__':
-    msg = main()
-    print(msg)
-    #mainloop()