No box required.
Make a strategic introduction of one great colleague to the other, out of the blue, unexpectedly, as a surprise token of friendship to bring two (or more) great people together to collaborate or do business.
Your referral means a lot more if you mean a lot to both parties. Here’s an example of one connection of two people who did not know each other, using myself as a fulcrum, just recently made via LinkedIn (only 1 name has been changed; contact Brett Deutsch as my preferred headshot photographer, a happy holiday gift from me to you–and Brett who reads me here–with my compliments).
Please disregard the typo: