Here's an old but great way of making a weird but colourful pattern - a psychedelic ripple pattern.

You will need:
  • paper
  • black pen
  • felt tips
Take a black felt pen, and draw a sort of blob shape in the middle of the paper.
Give your blob two ears, by drawing around it.

It'll look something like a wobbly butterfly.
Repeat again and again, until you can fit no more onto the paper.
Colour each individual section of the pattern in different ways.
When you've coloured every one, you'll have something amazing like this. You don't need to stop there - you'll get different patterns every time if you just experiment.

Try it yourself!