9 and 10 year olds.
The Fibonacci sequence is an interesting area to study. I found an excellent You Tube and showed the children after they had made an observational drawing of the spiral end of a shell.
I gave them some graph paper and they drew the first few squares as they saw it on the You Tube clip, until they ran out of room.
They also attempted the spiral. Harder than it looks.
They attempted to make the Fibonacci squares on an A3 page until there were 7 or 8 squares. One for each letter of their name. This was a real challenge as the smallest square doesn't begin in the middle of the page. We went through a lot of newsprint practice paper. I ended up giving some of them a loose template to trace over. I asked the children what I could have done differently if we had the day again. They said to give out the templates at the beginning. But I feel there would have been a lot of learning that would have been missed.