Dedicated to the smart you revised edition.

Number one red heart 2 red heart 4 red heart 6 red heart 10 club 3 club 8.

Spades 7 clubs 7 spades 5 diamonds 5 spades j hearts j clubs j.

Club q diamond q

A knows the number of points, but doesn't know which card it is, which means that the card drawn by C is not hearts 2 four of hearts hearts 6 hearts 10 clubs 3 clubs 8.

B said he knew that A didn't know that the color of the instruction card was square.

1 Suppose B holds clubs 7, and he is not sure that A holds clubs 7, then A may know.

Suppose B holds a heart, then he is not sure that A holds a heart J, then A may know.

That leaves seven spades, five spades, j diamonds, five diamonds, q.

Because A knows the number of cards and what the card is, it means that this card is in the 7 of spades and the Q of the J of spades.

If B's is spades, then he is not sure whether A's is spades 7.

Or the j of spades? Only when B holds the diamond card can he know that this card is a Q of diamonds.