I seriously took 2 minutes to prepare. I have just dumped a magnet basket on a tray and popped 3D cards.
Polygon - a shape that has the same number of corners and sides. Also known as a zigzag line that is closed.
You can use any materials you have at home to build it. I used playdough and cut up straws, but toothpicks and playdough or small marshmallows work as good.
Geomag is great! You can use metal balls for vertices and magnetic sticks for sides. Look at the shape first and count how many vertices and sides will you need to build them. Use desired mathematical language.
These are really lovely to explore the properties of the shapes as they are ready to use. You can also join them to build 3D shapes.