A small Christmas' Tree Algorithm in Python.

christmastree.py

import turtle

screen = turtle.Screen()
screen.setup(800,600)

circle = turtle.Turtle()
circle.shape('circle')
circle.color('red')
circle.speed('fastest')
circle.up()

square = turtle.Turtle()
square.shape('square')
square.color('green')
square.speed('fastest')
square.up()

circle.goto(0,280)
circle.stamp()

k = 0
for i in range(1, 17):
    y = 30*i
    for j in range(i-k):
        x = 30*j
        square.goto(x,-y+280)
        square.stamp()
        square.goto(-x,-y+280)
        square.stamp()

    if i % 4 == 0:
        x =  30*(j+1)
        circle.color('red')
        circle.goto(-x,-y+280)
        circle.stamp()
        circle.goto(x,-y+280)
        circle.stamp()        
        k += 2

    if i % 4 == 3:
        x =  30*(j+1)
        circle.color('yellow')
        circle.goto(-x,-y+280)
        circle.stamp()
        circle.goto(x,-y+280)
        circle.stamp() 

square.color('brown')
for i in range(17,20):
    y = 30*i
    for j in range(3):    
        x = 30*j
        square.goto(x,-y+280)
        square.stamp()
        square.goto(-x,-y+280)
        square.stamp()        
        
turtle.exitonclick()

Thanks!

Try this mate

Sorry
Wrong one

import turtle
s=turtle.Screen()
t=turtle.Turtle()
t.color("darkgreen")
#one way to draw a tree
t.begin_fill()
points=[ [0,400], [-200,300],[-100,300],[-300,200],[-100,200],
[-400,0],[400,0],[100,200],[300,200],[100,300], [200,300],[0,400]]#first and last points are the same
for each in points:
t.goto(each)
t.end_fill()

t.penup()
t.color("brown")

t.begin_fill()
points=[ [100,0], [-100,0], [-100,-100], [100,-100],[100,0]]#first and last points are the same
for each in points:
t.goto(each)
t.end_fill()

light=turtle.Turtle()
light.shape("circle")
light.color("yellow")
light.penup()
light.goto(-200,300)

light=turtle.Turtle()
light.shape("circle")
light.color("yellow")
light.penup()
light.goto(-300,200)

light=turtle.Turtle()
light.shape("circle")
light.color("yellow")
light.penup()
light.goto(-400,0)

light=turtle.Turtle()
light.shape("circle")
light.color("yellow")
light.penup()
light.goto(400,0)

light=turtle.Turtle()
light.shape("circle")
light.color("yellow")
light.penup()
light.goto(300,200)

light=turtle.Turtle()
light.shape("circle")
light.color("yellow")
light.penup()
light.goto(200,300)

s.mainloop()

No offence christmastree.py, but mine is much better