The following is an example of using an user-defined function to be called multiple(∞) times in a script with ease.
import turtle, time, random #tell python we need 3 different modules
turtle.speed(0) #set draw speed to the fastest
turtle.colormode(255) #special colormode
turtle.pensize(4) #size of the lines that will be drawn
def triangle(size): #This is our own function, in the parenthesis is a variable we have defined that will be used in THIS FUNCTION ONLY. This fucntion creates a right triangle
turtle.forward(size) #to begin this function we go forward, the amount to go forward by is the variable size
turtle.right(90) #turn right by 90 degree
turtle.forward(size) #go forward, again with variable
turtle.right(135) #turn right again
turtle.forward(size * 1.5) #close the triangle. thanks to the Pythagorean theorem we know that this line must be 1.5 times longer than the other two(if they are equal)
while(1): #INFINITE LOOP
turtle.setpos(random.randint(-200, 200), random.randint(-200, 200)) #set the draw point to a random (x,y) position
turtle.pencolor(random.randint(1, 255), random.randint(1, 255), random.randint(1, 255)) #randomize the RGB color
triangle(random.randint(5, 55)) #use our function, because it has only one variable we can simply put a value in the parenthesis. The value that will be sent will be random between 5 - 55, end the end it really just changes ow big the triangle is.
turtle.pencolor(random.randint(1, 255), random.randint(1, 255), random.randint(1, 255)) #randomize color again