My two youngest grandkids are only eleven months apart and for four weeks each year, they are the same age! Because of that, they generally get a combined party now and again...
As they are into totally different things, I tried my best to think up something that would show that! My older sister is 'the artistic' one, so I just helped with the painting (her telling me what to do of course).
We started with old cardboard boxes, cutting them out with an electric bread knife!
I think the whole party evening went down well... I hope they also enjoyed their cakes too!