A delightful puzzle – thanks again to Pallav Pandey! Also for a change, I had a chance to work on a puzzle myself as someone else contributed. I loved solving the puzzle along with my 11 year old daughter Anisha. I got answers from three other people, who all gave partially correct answers – Prateek Poddar, Suman Saraf and Karan Sharma – all very smart and regular folks providing answers.
I am attaching a link to the video which gives the solution for children.
For others, here is a potential way to do this, and would request Pallav to send me the answer that he knows.
Since there are 5 cards and 4 colors/ suits, there will be at least one color for which we have two or more cards. M1 can give back a card of that color to the audience and keep the other one as the first card in the sequence to communicate the color to M2. That was easy and everyone got that.
Notice that these are rectangular cards, and therefore can be placed in two orientation – vertical and horizontal. We can use these two possibilities to denote a “1” or a “0” and therefore use the binary number method to communicate the value of the card using the 4 cards we have (including the first one that communicates the color).
Hope you all enjoyed the puzzle!