How to announce baby #6?

I am wanting to have a fun way to announce baby #6 due March 2018. I am currently 13 weeks and we haven't said anything to anyone yet, but somehow my mother-in-law can smell it on me or something 😆. So she is the only one that knows currently. We already have 3 girls and 2 boys, I really want another boy just to even things out, plus our current youngest 16 months old, could have another boy to run around with.

I was thinking maybe a Brady bunch squares picture? I did the oops we did it again with baby#5.

Also, I am thinking to not announce until maybe 16 or 20 weeks. We'd love to know the gender first. Please give me some ideas. Thank you!!