"The expression on your face, Watson, coupled with the sheet of foolscap in your hand, leads me to deduce that you are quite puzzled about something."
"Indeed I am, Holmes. Perhaps you can make head or tail of it; I have got nowhere so far. Here..."
"Thank you. Oh, this is quite clear. The answers to the questions at the bottom are..."
What?
Here is the text on the sheet of foolscap; it is only the text that is relevant, not the handwriting, color, spacing, et cetera.
VALID WORDS INVALID WORDS
BEAT STRIKE
CYLINDER TUBE
TICS TWITCHES
BOGS MARSHES
COPPER PENNY
SILVER GOLD
ALIASES NICKNAMES
1. IS 'VALID' A VALID OR INVALID WORD?
2. WHAT IS THE CRITERION FOR VALIDITY?