And you could even use these functions to check their own outputs and these functions again to check those outputs in turn, and these functions again to check t

And you could even use these functions to check their own outputs and these functions again to check those outputs in turn, and these functions again to check those outputs in turn, and these functions again to check those outputs in turn, and these functions again to check those outputs in turn, and these functions again to check those outputs in turn, and on, and on...