I only learned about making a "Crown of Thorns" last year thanks to the ladies at 4Real.
This is a visual reminder of Our Lord's suffering...for US.
Using a salt dough that I had made, each child constructed a crown and inserted toothpicks. It represents Jesus' crown of thorns. For each sacrifice and good deed, they can pull a toothpick out of the crown.
The goal is to have all the toothpicks out by Easter Sunday and replace the toothpicks with flowers. This year, each children painted their crown and toothpicks brown to look more realistic.