1449.sagews

x, y = var('x, y')

def nrmsquirt(x,y):
    return sqrt(x^2 + y^2)

def EL(A,m,n,d):
    B=[A[0]]
    v=[-d]
    t=1/n
    for h in range(1,n):
        B.append([h*t*A[0][0]+(1-h*t)*A[1][0],h*t*A[1][1]+(1-h*t)*A[0][1]])
    for j in range(1,m):
        for k in range(1,n):
            B.append([k*t*A[j-1][0]+(1-k*t)*A[j][0],k*t*A[j-1][1]+(1-k*t)*A[j][1]])
    for r in range(1,n):
        B.append([h*t*A[m][0]+(1-h*t)*A[0][0],h*t*A[0][1]+(1-h*t)*A[0][1]])
    for i in range(0,m):
        v.append(sqrt((x-B[i][0])^2+(y-B[i][1])^2))    
    return sum(v)

contour_plot(EL([[-1,0],[-1,2],[1,1],[1,0]],4,2,0),(x,-2, 2), (y,-2, 2),contours=30,plot_points=100)

range(0,3)

[0, 1, 2]