Arduino Error (C++) : invalid use of non-static data member

I am making a scalable Arduino library but I receive the compiler-error: invalid use of non-static data member.

My Code: LedCube.h:

#ifndef LedCube_h
#define LedCube_h
#include "Arduino.h"
class LedCube {
  private:
  int _x, _y, _z;
  byte _lPins[_y];
  byte _cPins[_z][_x];
  public:
  LedCube(int x, int y, int z, byte *lPins, byte (*cPins)[_x]);
  void displayFrame(bool frame[][_x][_z]);
  void displayLayer(int i, bool frame[][_x][_z]);
};
#endif

Ledcube.ino(cpp):

#include "Arduino.h"
#include "LedCube.h"

int _x, _y, _z;
//bool frame[y][z][x] = {0};
byte _lPins[_y];
byte _cPins[_z][_x];

LedCube::LedCube(int x, int y, int z, byte lPins[], byte cPins[][_x]) {
  _x = x;
  _y = y;
  _z = z;
  _lPins = lPins;
  _cPins = cPins;
}

void LedCube::displayFrame(bool frame[_y][_x][_z]) {
  int i;
  for(i=0;i<_y;i++) {
    displayLayer(i, frame);
    pinMode(_lPins[i], OUTPUT);
    delay(1);
    pinMode(_lPins[i], INPUT);
  }
}

void LedCube::displayLayer(int i, bool frame[_y][_x][_z]) {
  int j,k;
  for(j=0;j<_z;j++) {
    for(k=0;k<_x;k++) {
      if(frame[i][j][k]) {
        digitalWrite(_cPins[j][k], HIGH);
      }
      else {
        digitalWrite(_cPins[j][k], LOW);
      }
    }
  }
}

I want to accept the variables x, y and z and set these to _x, _y and _z in the constructor, and hence do not want to set the variables static. I am using these variables to declare a loop.

The error I get is:

Arduino: 1.6.5 (Windows 10), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"

In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_y'
   int _x, _y, _z;
           ^
LedCube.h:13: error: from this location
   byte _lPins[_y];
               ^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
   int _x, _y, _z;
               ^
LedCube.h:14: error: from this location
   byte _cPins[_z][_x];
               ^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
   int _x, _y, _z;
       ^
LedCube.h:14: error: from this location
   byte _cPins[_z][_x];
                   ^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
   int _x, _y, _z;
       ^
LedCube.h:16: error: from this location
   LedCube(int x, int y, int z, byte *lPins, byte (*cPins)[_x]);
                                                           ^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
   int _x, _y, _z;
       ^
LedCube.h:17: error: from this location
   void displayFrame(bool frame[][_x][_z]);
                                  ^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
   int _x, _y, _z;
               ^
LedCube.h:17: error: from this location
   void displayFrame(bool frame[][_x][_z]);
                                      ^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
   int _x, _y, _z;
       ^
LedCube.h:18: error: from this location
   void displayLayer(int i, bool frame[][_x][_z]);
                                         ^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
   int _x, _y, _z;
               ^
LedCube.h:18: error: from this location
   void displayLayer(int i, bool frame[][_x][_z]);
                                             ^
LedCube:6: error: array bound is not an integer constant before ']' token
LedCube:7: error: array bound is not an integer constant before ']' token
LedCube:7: error: array bound is not an integer constant before ']' token
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
   int _x, _y, _z;
       ^
LedCube:9: error: from this location
LedCube.ino: In constructor 'LedCube::LedCube(...)':
LedCube:10: error: 'x' was not declared in this scope
LedCube:11: error: 'y' was not declared in this scope
LedCube:12: error: 'z' was not declared in this scope
LedCube:13: error: '_lPins' was not declared in this scope
LedCube:13: error: 'lPins' was not declared in this scope
LedCube:14: error: '_cPins' was not declared in this scope
LedCube:14: error: 'cPins' was not declared in this scope
In file included from LedCube.ino:2:0:
LedCube.h: At global scope:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_y'
   int _x, _y, _z;
           ^
LedCube:17: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
   int _x, _y, _z;
       ^
LedCube:17: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
   int _x, _y, _z;
               ^
LedCube:17: error: from this location
LedCube.ino: In member function 'void LedCube::displayFrame(...)':
LedCube:20: error: 'frame' was not declared in this scope
LedCube:21: error: '_lPins' was not declared in this scope
In file included from LedCube.ino:2:0:
LedCube.h: At global scope:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_y'
   int _x, _y, _z;
           ^
LedCube:27: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
   int _x, _y, _z;
       ^
LedCube:27: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
   int _x, _y, _z;
               ^
LedCube:27: error: from this location
LedCube.ino: In member function 'void LedCube::displayLayer(...)':
LedCube:31: error: 'frame' was not declared in this scope
LedCube:31: error: 'i' was not declared in this scope
LedCube:32: error: '_cPins' was not declared in this scope
LedCube:35: error: '_cPins' was not declared in this scope
invalid use of non-static data member 'LedCube::_y'

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I just want to target this error and not the others in the output.