code: function makeMatrix(columns, rows) {
    let matrix = [];
    for (let i = 0; i < columns; i++) {
      let column = [];
      for (let j = 0; j < rows; j++) {
        column.push(0);
      }
      matrix.push(column);
    }
    return matrix;
  }
docs: Create a new column x row matrix.
  
  @private
  @param {number} columns
  @param {number} rows
  @return {Array<Array<number>>} matrix
  @example
  makeMatrix(10, 10);