def _remove_border_columns(axs, col_size):
    """Removes the border columns, returning the remaining columns."""
    num_cols = axs.shape[1]
    border_indices = list(range(col_size, num_cols, col_size+1))
    border_axs = axs[:, border_indices].reshape(-1)
    [ax.remove() for ax in border_axs]
    data_indices = [col for col in range(num_cols) if col not in border_indices]
    return axs[:, data_indices]