And some intermediate steps. Here's all the bits ready for construction. I broke my own rule and did my own cake mix (instead of a box mix, which is more reliable for structural cakes). The squares indeed came out a bit flat and heavy.
Lots of buttercream frosting with lots of red and blue food colouring in it.
Add the chocolate coated icecream cones. I used a ganache recipe to make the chocolate coating (chocolate and cream melted together).
And once more - the finished result. My daughter helped with the final decorations.