One nice example is whitespace. In the language proper, any combination of operators are valid. The operators are space, tab and newline (specifically "\n"). All other characters are considered comments.

This answer, and indeed your question (as well as this entire web page) are examples of valid whitespace programs (though they may not do anything particularly interesting).

One nice example is whitespace. In the language proper, any combination of operators are valid. The operators are space, tab and newline (specifically "\n"). All other characters are considered comments.

This answer, and indeed your question (as well as this entire web page) are examples of valid whitespace programs (though they may not do anything particularly interesting).