Cut three pieces of cotton string a little shorter than your jars. Dip them in water, roll them in sugar and let them dry completely, about an hour. This "seeds" them.

Grown-up job: heat the water in a saucepan, then stir in the sugar a cup at a time until it is completely dissolved and the syrup is clear. Bring to a gentle boil, then take off the heat.

Let the syrup cool for 20 minutes, then stir in the peppermint and pour into the jars. Add a drop of coloring to some jars.

Tie each string to a skewer, rest it across the jar top and lower the string into the syrup without touching the sides or bottom. A clothes peg holds it steady.

Leave the jars somewhere quiet and check daily. After 5 to 7 days, lift the crystals out, let them dry on parchment, and tie ribbons on to hang.