How can I make the petals diamond shaped rather than an oval

I’m trying to use patterns to create a flower with diamond shaped petals but these oval shaped ones are the closest I’ve been able to get. I was wondering if anyone could help or provide any feed back with this.

Flower I’m trying to create

Flower I'm trying to create

Code:

import turtle
def petal(t, r, angle):
    for i in range(2):
        t.circle(r,angle)
        t.left(180-angle)

def flower(t, n, r, angle):
    for i in range(n):
        petal(t,r,angle)
        t.left(360.0/n)

def move(t, length):
    window = turtle.Screen()
    window.bgcolor("Yellow")
    t.pu()
    t.fd(length)
    t.pd()

sam = turtle.Turtle()

sam.speed(99)

move(sam, -150)

sam.color("red")
move(sam, 150)
flower(sam, 10, 40.0, 100.0)

Answer

Use straight movements in the petal function:

def petal(t,d,a):
    for _ in range(2):
      t.fd(d)
      t.left(a)
      t.fd(d)
      t.left(180-a)

note: the flower looks closer to your objective with an angle of 60 instead of 100