The Wizard's Hat

A lady wizard has sixteen different hats. Four hats are yellow, four are red, four are blue, and four are green. Four hats have a plus sign on them, four have a minus sign, four have a multiplication sign, and four have a division sign (she's a math wizard). No two hats of the same colour have the same sign on them.

She has a special packing crate with sixteen compartments to store the hats. The compartments form four rows and four columns. When she packs the crate she puts one hat in each compartment in such a way that every row and column has four different coloured hats and four different arithmetic signs.

She has started to put the hats in the crate. The picture shows where she has put four of the hats. Can you finish packing the crate for her?