With the platinum jubilee here, it is time to make red, white and blue bunting, but why settle for that, why not embed a message of your choice in your bunting. To do this you need to invent a code that converts sequences of colours into letters.
With three bunting flags and three colours there are just enough combinations (27 – 3 cubed) to cover all the letters of the alphabet with one left over to mean a space. We just need to decide a specific way to map letters to triples. We could do any, but perhaps the best is to use a ternary encoding like our decimal (and also binary).
Imagine counting with only three digits, 0, 1 and 2. When we get to 2, to count one further we carry a 1 into the next column and go back to 0. When we get to 2 again we will carry another 1, turning the 1 in that second column to a 2. When we do it again, that 2 will go back to 0 and carry over into the third column. The full set of numbers 0-27 and so letters A-Z and space are then as shown below.
By using three colours, red, white and blue in place of 0, 1 and 2, so for example 0 is red, 1 is white and 2 is blue (as above), we get a mapping of letters onto triples of colours. Then, E for example is represented by RED-WHITE-WHITE and R is WHITE-BLUE-BLUE, so to spell out ER with this code would mean a string of bunting with colours:
To make a string of bunting you just need to cut out lots of triangles with tabs from coloured paper, and fasten them on to strings. Here is ER in bunting
You can spell out any message you like this way as long as you have enough bunting.
Perhaps you would like to represent digits too (or upper and lower case or punctuation). If so you just need more than three flags per character: invent your own colour code to do it.
Here is a blank template for printing three flags per A4 sheet: