Trivia cards for the original Think-a-Tron were pretty small at just 1 1/4 x 2 1/2 inches.

As has been mentioned, the punched holes and corner cut were just for show, only the notch on the right mattered. I wonder how long it took the kids "playing" Think-a-Tron to figure this out? The cards were also two sided.  150 cards (300 questions) shipped in the box. Additional sets of 50 cards (100 questions) on specific topics like sports could be purchased separately.

I had to decide what kind of cards to use for Think-a-Tron 2020.  Some criteria:

• The answer had to be part of the question card and should not be too easy to figure out, like the "notch" was. 
• I needed to be able to somehow "read" the answer from the card. 
• The trivia cards should be easy for anyone to create.  

After considering this for a while, I settled on the following:

• Think-a-Tron 2020 trivia cards will use a standard business card format of 3 1/2 x 2 inches. I chose this size because blank card stock and word processing templates are readily available. The larger size will also allow for more easily readable questions (old eyes).
• Questions will appear on the front of the card, and answers on the back, so only a single question per card.
• Answers will be encoded as QR codes. I considered bar codes but I think that QR codes are cooler looking.

So I purchased some blank business card stock (Avery 5371) and using MS Word with the Avery template created some test cards.  Seen here are the front of the printed sheet on the left and back on the right.

The QR codes were created online at the QR Code Generator site. I created one QR code image for each of the possible answers (A, B, C, T, F).  It should be noted that it is still possible at this point to figure out the correct answer by looking carefully at the QR code. This is because the "payload" for each is just a single letter. My plan is to write an application to automate the creation of these cards at which time I will obfuscate the payload by adding some random "noise" to each answer.

So I ripped along the dotted lines and viola I have a small test deck of trivia cards to work with.

Next up, reading the QR codes.