Here's what I've been doing all week.I bought the craft foam from Al-Rawnaq Trading (Doha, Qatar) and downloaded the templates from here:
I used contact cement to stick the craft foam on to the magnetic sheet (in this case I used a magnetic whiteboard, the types you put on the refrigerator). I bought the whiteboard from Daiso. Then waited a day for all of the triangles to dry and cut them.
I also bought the magnetic whiteboard (the thicker one) from Daiso. This will be the 'working mat'.
Then printed out 'guides' per set: Triangle Box #1, #2, #3 and #4
I separated the triangles too. Each 'box' in a sandwich bag and all of them in a rectangular plastic container.
The children can use the guide to construct the shapes.
This is how it should be packed away on the shelf.