You know how to write music down using music notes and the music stave.
Can you design your own system for writing down music? You need to show what note to play and how long to play it for. You can use pictures, colours, symbols, whatever you like.
Here I have used pictures to represent the notes A 🍎, B🍔, C🧁. The gaps between the notes show how long they should be. A rest (or silence) is shown as X.
🍎 🍎 🍔🍔🧁 🍎 🍔 X 🍔🧁🍎🍔 🍎 X
This isn’t a perfect way of drawing music. You can’t see exactly how long each note should be, but you can see what the notes are. However if you can play more than one A, B or C on your instrument you wouldn’t be able to tell which one.