Rebus is a Latin word meaning 'by things'. So, in the word game called rebus, the words are replaced 'by things'. You don't read the letters as words, you read them as things. Here is a well-known example of a rebus:
This means 'Too wise [two Y's] you are [UR], too wise you be [UB], I see you are [ICUR] too wise for me [4 me]'.
But you can make your rebus a lot more complicated than that. For instance,
means 'You're under arrest', and
means 'Dover (D-over) Castle'.
You can also use simple little sketches to take the places of words. Draw an eye for T, a nose for 'knows', a deer for 'dear', or a clock face to mean 'time'. Build up words by putting two of these sketches together: a foot and a ball for 'football', or a letter 'N' and an ear for 'Near'. The possibilities are endless.
In this way, you can write letters, stories and messages. Each person can make up his own and then pass it to his neighbour to read.