for (int i = 0; i < mf.mesh.uv.Length; i += 4)
        {
            float offsetX = UnityEngine.Random.Range(0, maxTexturesX - 1);
            float offsetY = UnityEngine.Random.Range(0, maxTexturesY - 1);

            newUVs[i] = new Vector2(offsetX * basicUVSizeX, offsetY * basicUVSizeY);
            newUVs[i + 1] = new Vector2((offsetX + 1) * basicUVSizeX, offsetY * basicUVSizeY);
            newUVs[i + 2] = new Vector2(offsetX * basicUVSizeX, (offsetY + 1) * basicUVSizeY);
            newUVs[i + 3] = new Vector2((offsetX + 1) * basicUVSizeX, (offsetY + 1) * basicUVSizeY);
        }