NRICH Webinar, December 12th 2018

On Wednesday 12th December 2018, Liz and Alison presented a problem to classes around the world watching our live stream, and invited participants to send in their comments and solutions. 

Here is the video (the warm-up task is on screen for the first 8 minutes or so, and Liz and Alison begin presenting after that):

Once you've watched the video, you might like to take a look at Magic Crosses, and the solutions that were submitted by other people.