```python
import numpy as np
from simsopt.geo.surfacerzfourier import SurfaceRZFourier
from simsopt.field.coil import Current, Coil, ScaledCurrent
from simsopt.field.biotsavart import BiotSavart
from simsopt.geo.curve import curves_to_vtk
from simsopt.objectives.fluxobjective import SquaredFlux
from simsopt.objectives.curveobjectives import CurveLength, MinimumDistance
from scipy.optimize import minimize
from simsopt.geo.curvecorrected import create_multifilament_grid

# Initialize boundary magnetic surface
nfp = 1  # Number of field periods
nphi = 16
nzeta = 16
surface = SurfaceRZFourier(nphi=nphi, nzeta=nzeta, nfp=nfp, mpol=3, ntor=3)
surface.set_coeffs(np.random.randn(*surface.coeffs.shape))

# Create equally spaced curves and multifilament grid
num_coils = 3
num_filaments = 10
coils = []
for i in range(num_coils):
    coil = Coil(surface.sample(2*np.pi*i/num_coils, 0.1), 1.0)
    coils.append(coil)
    create_multifilament_grid(coil, num_filaments)

# Apply stellarator symmetry
for coil in coils:
    coil.current = ScaledCurrent(Current(1e5), 1.0)

# Define Biot-Savart law
bs = BiotSavart(coils)
bs.set_points(surface.gamma())

# Define objective function
def objective(x):
    for i, coil in enumerate(coils):
        coil.current.set_value(x[i])
    squared_flux = SquaredFlux(surface, bs)
    curve_length_penalty = sum(CurveLength(coil.curve) for coil in coils)
    coil_to_coil_distance_penalty = MinimumDistance(coils, 0.1)
    return squared_flux.J() + curve_length_penalty.J() + coil_to_coil_distance_penalty.J()

# Perform Taylor test
from simsopt.util.taylortest import taylortest
taylortest(objective, np.random.rand(num_coils), dobjective_dx=objective)

# Run optimization
x0 = np.array([coil.current.get_value() for coil in coils])
res = minimize(objective, x0, method='L-BFGS-B')

# Update coil currents after optimization
for i, coil in enumerate(coils):
    coil.current.set_value(res.x[i])

# Save output in VTK format
curves_to_vtk(coils, "optimized_coils.vtk")
```