Joachim once launched an open call for a mural which would be created for a TV-show. The school responded positively but he had alreday found one.
They never gave up and kept asking the artist for some cool art. Joachim then decided to do it on his own.
He painted a swordfish because that was an appropriate fit for this shape of wall. But it's also a perfectly reflects the school's vision: 
"We want to teach the children to think beyond what they would expect. In this case, that artworks can not only be found in museums, but also on the streets, and even on the facade of their cool school" says one of the teachers.
And who doesn't agree on that....