First I took a leftover shelf from IKEA and painted the entire thing white. I then put a second coat of white on the second and 4th slats. Afterwards, I wrapped the second and fourth slats with paper to protect them from the red paint and painted the other three slats red.
I then painted a wooden 4, a 1/4 inch 7x7 square and a wooden star white. The 4 and the square got a coat of blue on top of that.

Then I sanded all pieces and glued them together. A little jute string for a finishing touch.