The dot matrix printer pattern method

Way before today’s new-fangled laser printers, we all used to rely on chugging, noisy dot matrix printers. And reams of green and white stripy paper. Dot matrix printers did their printing with multiple tiny rods that put down a series of dots. These dots loosely formed recognisable characters, without actually being anything more than a bunch of impressions on a page.

We can use the same approach to use letters and numbers directly on the hints.

This is what the English alphabet looks like...

And this is what the numbers look like...

Note that there is usually a decision to be made about where in the card to locate the start of the letter or number. If you are going to use this method to generate a pattern, be sure to vary the location of the characters. Remember, your pattern needs to be impossible to guess, so combine a letter or number with some other sequence to ensure your pattern remains your secret.