Looking for something to do with the kids on a miserable wet day? What about designing a T-Shirt.
If you reach out and grab an Artline T-Shirt Marker, you could while away a couple of hours. They have 2mm polyester fiber bullet tips tightly covered with a handy airtight cap that can be posted on the end of the barrel when in use. As you would expect the pigment ink is waterproof & can be washed at 60 degrees C (as long as the ink has been fixed), it’s also fadeproof.