Perlin Noise Gradient Generating Issues

Question

It appears to be an issue with the gradients from what I can see. I'm not really sure what to do about this, but the gradients are in a 4x4 grid, and they are not matching with it's neighboring gradient (generated the wrong direction?). I've tried and tried to look for answers, but could only find one other post on Stackoverflow that has something similar to my issue. Here is my code that I'm using:

using UnityEngine;
using System;
using System.Collections;

public class Noise : MonoBehaviour {

private const int GradientSizeTable = 256;
private System.Random random;
private readonly double[] _gradients = new double[GradientSizeTable * 3];
private readonly int[] perm = new int[] {
    225,155,210,108,175,199,221,144,203,116, 70,213, 69,158, 33,252,
    5, 82,173,133,222,139,174, 27,  9, 71, 90,246, 75,130, 91,191,
    169,138,  2,151,194,235, 81,  7, 25,113,228,159,205,253,134,142,
    248, 65,224,217, 22,121,229, 63, 89,103, 96,104,156, 17,201,129,
    36,  8,165,110,237,117,231, 56,132,211,152, 20,181,111,239,218,
    170,163, 51,172,157, 47, 80,212,176,250, 87, 49, 99,242,136,189,
    162,115, 44, 43,124, 94,150, 16,141,247, 32, 10,198,223,255, 72,
    53,131, 84, 57,220,197, 58, 50,208, 11,241, 28,  3,192, 62,202,
    18,215,153, 24, 76, 41, 15,179, 39, 46, 55,  6,128,167, 23,188,
    106, 34,187,140,164, 73,112,182,244,195,227, 13, 35, 77,196,185,
    26,200,226,119, 31,123,168,125,249, 68,183,230,177,135,160,180,
    12,  1,243,148,102,166, 38,238,251, 37,240,126, 64, 74,161, 40,
    184,149,171,178,101, 66, 29, 59,146, 61,254,107, 42, 86,154,  4,
    236,232,120, 21,233,209, 45, 98,193,114, 78, 19,206, 14,118,127,
    48, 79,147, 85, 30,207,219, 54, 88,234,190,122, 95, 67,143,109,
    137,214,145, 93, 92,100,245,  0,216,186, 60, 83,105, 97,204, 52};

public void pNoiseSeed(int s)
{
    seed = s;
}
private int seed;

public double pNoise(double x, double y, double z)
{
    random = new System.Random(seed);
    InitGradients();

    int ix = (int)Math.Floor(x);
    double fx0 = x - ix;
    double fx1 = fx0 - 1;
    double wx = Smooth(fx0);

    int iy = (int)Math.Floor(y);
    double fy0 = y - iy;
    double fy1 = fy0 - 1;
    double wy = Smooth(fy0);

    int iz = (int)Math.Floor(z);
    double fz0 = z - iz;
    double fz1 = fz0 - 1;
    double wz = Smooth(fz0);

    double vx0 = Lattice(ix, iy, iz, fx0, fy0, fz0);
    double vx1 = Lattice(ix + 1, iy + 1, iz + 1, fx1 + 1, fy0 + 1, fz0 + 1);
    double vy0 = Lerp(wx, vx0, vx1);

    vx0 = Lattice(ix, iy + 1, iz, fx0, fy1, fz0);
    vx1 = Lattice(ix + 1, iy + 1, iz, fx1, fy1, fz0);
    double vy1 = Lerp(wx, vx0, vx1);

    double vz0 = Lerp(wy, vy0, vy1);

    vx0 = Lattice(ix, iy, iz + 1, fx0, fy0, fz1);
    vx1 = Lattice(ix + 1, iy, iz + 1, fx1, fy0, fz1);
    vy0 = Lerp(wx, vx0, vx1);

    vx0 = Lattice(ix, iy + 1, iz + 1, fx0, fy1, fz1);
    vx1 = Lattice(ix + 1, iy + 1, iz + 1, fx1, fy1, fz1);
    vy1 = Lerp(wx, vx0, vx1);

    double vz1 = Lerp(wy, vy0, vy1);
    return Lerp(wz, vz0, vz1);
}

private void InitGradients()
{
    for (int i = 0; i < GradientSizeTable; i++)
    {
        double z = 1f - 2f * random.NextDouble();
        double r = Math.Sqrt(1f - z * z);
        double theta = 2 * Math.PI * random.NextDouble();
        _gradients[i * 3] = r * Math.Cos(theta);
        _gradients[i * 3 + 1] = r * Math.Sin(theta);
        _gradients[i * 3 + 2] = z;
    }
}

private int Permutate(int x)
{
    const int mask = GradientSizeTable - 1;
    return perm[x & mask];
}

private int Index(int ix, int iy, int iz)
{
    return Permutate(ix + Permutate(iy + Permutate(iz)));
}

private double Lattice(int ix, int iy, int iz, double fx, double fy, double fz)
{
    int index = Index(ix, iy, iz);
    int g = index*3;
    return _gradients[g] * fx + _gradients[g + 1] * fy + _gradients[g + 2] * fz;
}

private double Lerp(double t, double value0, double value1)
{
    return value0 + t * (value1 - value0);
}

private double Smooth(double x)
{
    return x * x * (3 - 2 * x);
}
}

Any help would be much appreciated! :)

Here's a picture: