Why do this problem?
This is a really good activity to engage all children. Those who are less motivated and find mathematics difficult will be able to have a go (and may well surprise you) but there is also enjoyment and intrigue here for the enthusiastic and mature mathematician!
The problem is good for developing pupils' ability to visualise, and depending on their experience, you may also want to use this as an opportunity to encourage them to use correct mathematical vocabulary relating to transformations.
This is a sheet
with four letters, though you could use other ones too.
Other simple C's I found were;
Just to carry on here is an H tessellation.
It's also good to look at what seem like very simple [maybe too simple, we think!] letters and find many ways of tessellating them. To show you the sort of thing I mean look at these variations on tessellating the simple letter L. I used four different orientations and coloured them to help.
The following questions might be useful in coaxing children to think more deeply, and perhaps differently, about what they are doing:
Could this tessellation be continued for ever? Why or why not?
What is the single repeating unit in the tessellation?
How would you describe the tessellation to someone else?