Uncaught TypeError: Cannot read property "drawHTMLBoard" of undefined

class Board {
  constructor(){
    this.rows = 6;
    this.columns = 7;
    this.spaces = this.createSpaces();
  }

  /**
  * Generates 2D array of spaces
  * @return {Array} An array of space objects
  */

  createSpaces(){
    const spaces = [];

    for(let x = 0; x < this.columns; x++){
      const col = [];

      for (let y = 0; y < this.rows; y++){
        const space = new Space(x, y);
        col.push(space);

      }
      spaces.push(col);
    }
    return spaces;

  }

  drawHTMLBoard(){
    for(let column of this.spaces){
      for(let space of column){
        space.drawSVGSpace();
      }
    }
  }
}

class Game {
  contructor(){
    this.board = new Board();
    this.players = this.createPlayers();
    this.ready = false;

    }

    /**
    * returns active player
    * @returns {Object} player - the active player
    */

    get activePlayer(){
      return this.players.find(player => player.active);

    }

    /**
    * Creates two player objects
    * @returns {Array} an array of two player objects
    */

    createPlayers(){
      const players = [new Player("Player 1", 1, "#e15258", true),
                       new Player("Player 2", 2, "#e59a13")];

      return players;
  }

  /*
  * gets game ready for play
  */
  startGame(){
    this.board.drawHTMLBoard();
    this.activePlayer.activeToken.drawHTMLToken();
    this.ready = true;

  }

}