I stocked up on hama beads (the ironable, plastic beads that kids often use to make shapes with. We have them at the 'dollar store' / 100 yen store here.
(There are some great ideas out there, but we wanted to keep it simple, but enjoyable enough for everyone. Playing with beads provides more entertainment for a 4 year old than using sharpies on a plate, although Aztec designs on a plate sounds like FUN!! Next time!)
The temptation was there to make the entire shape, but the class knew that we were making small beads so they stuck to the plan!
It was a great lesson in patterns and shapes, but more importantly, it was colourful and fun! Everyone was super happy with their new necklaces!!