For project 3 part 2, you will generate a plot with two independent variables and one dependent variable by adding 3D curves to the same VPython window across multiple runs of ising_model(..).

Below is a code skeleton to get you started.

from visual import display, curve
 
vpython_3d_line_window = display(title="VPython 3D Line Plot", autocenter=True)
 
def ising_model(N, totalEnergy, steps, vis=True):
 
    ...                                                # other initialization
 
    M = -2*N**2                                        # the magnetization (initial value is -2N²)
    m_vs_simSteps = curve(display=vpython_3d_line_window)  # note we specify the display initialized earlier outside ising_model
 
    for step in range(steps):
        for trial in range(N**2):
 
            ...                                        # do N**2 trials, keeping M up to date
 
        # we want to color the line red when M = +N² and white when M = -N².
        # this means that color(N²) = (1,0,0) and color(-N²) = (1,1,1)
        # so, scale the green and blue components linearly with M
        t = (1-(M/N**2.))/2
        m_vs_simSteps.append(pos=(step, M, totalEnergy), color=(1, t, t))